Cold-Pump it!!!! It helps tremendously (for awhile). Just be careful
not to go home while the valve is open (in case of a
power-outage...ouch!).
The process generally involves bringing-in a turbo-pumping station, and
pumping down everything in front of the valve, leak-checking, and then
you open the valve, and pump on the thing for several hours.
I always lose a few pounds (water weight...sweating) until the procedure
is completed. The bad news is that sometimes the seals are going (or
have gone) bad, so this just buys one a little extra time before the
magnet has to be brought down, warmed-up, and re-sealed.
Best Regards,
Rich S.
-- Richard Shoemaker, Ph.D. Phone--(402) 472-6255 Instrumentation Director, Chemistry FAX---- -6964 Research Associate Professor, Chemistry University of Nebraska-Lincoln URL: http://wwitch.unl.edu/nmrlab.html