Dear Tim
I was the one who initialy started the RV debate at that time.  We (Faculty
of Sciences) had purchased 10 pumps from Edwards in 94; 4 of those were
mine (2 RV5, 2 RV8).  They were replacements for 10 year old pumps on two
stable isotope mass specs.  Of the ten pumps ALL leaked within a year at
the shaft seal.  It was finally determined that the seals needed a spacer
to puch the seal away from its initial setting on the shaft.  Apparently
the shaft bevels slightly at that point.  The seal is sitting half on the
bevelled area which causes the seal to be improperly seated.  The spacer
they provided allowed two of the four to be fixed.  One RV5 and one RV8
were relegated to paperweight status as the fix didn't work.  Here is the
history that I sent Edwards:

"We have only kept a record of service since 1996 on these pumps.:
Model       Serial no              Date                Service
RV5             00580               Jan 10, 96       Shaft seal
                                             Apr 23, 96      Shaft seal
                                             Sept 27, 96     Shaft seal
RV5             01282               Jan 10, 96       Shaft seal
                                             Apr 23, 96      Shaft seal
                                             Sept 27, 96     Shaft seal
RV8            01067               Jan 10, 96        Shaft seal
                                            Apr 23, 96       Shaft seal
                                            Sept 27, 96      Shaft seal
RV8            01190              Jan 10, 96        Shaft seal
                                            Feb 21, 96       Shaft seal
                                            Apr 23, 96       Shaft seal
                                            Sept 27, 96      Shaft seal

Pumps received with Edwards SuperGrade "A" Oil.   The Oil broke down within
one to two months to an almost water state.  Sight glass became brown and
needed to be removed and cleaned.  The shaft seals started leaking on one
RV and it was sent to Vacuum Science for warranty repair.  The RV pump was
returned and started leaking within two months.  Contact with our sales rep
at the time (Dave Morris) 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.  By that time
the warranty ran out.  We changed all shaft seals and got some No. 19 oil.
 This solved the oil breakdown but not the shaft seal problem.

The RV8 (01190) that was sent for warranty repair has had its shaft seal
replaced six times.  It leaks within 2 weeks each time.  Our pump
specialist has tried everything to stop the leaks.  It is now a useless
$2000 paperweight that has barely run 13 months in three years along with
an RV5 (01282)"

Edwards has since replaced all 4 with new ones Summer 98.  All new ones are
in large turkey basting pans to catch the oil (if needed).  All have not
leaked since (knock on wood).  They were supposed to call me with an
explanation on the four pumps, especially the 2 irrepairable ones...
nothing yet

Gilles







Gilles St-Jean
Technologue / Technologist
Laboratoires d'isotopes- G.G. Hatch -Isotope Laboratories
U d'Ottawa / U of Ottawa
Dept des Sciences de la Terre / Dept of Earth Sciences
140 Louis Pasteur, Ottawa, Ontario, Canada, K1N 6N5
Bureau / Office: (613) 562-5800 ext. 6839
Labo / Lab                                    ext. 6836
Fax:                   (613) 562-5192
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