The conditions you describe are classic to a thermal "touch" between the
nitrogen vessel and the bore of the magnet (or where ever you observe the
ice). Additional pumping will not help. Most likely, one of the fiberglas
support rods at the bottom of the magnet has become loose or broken. Or it
may be due to an ice bridge. The only fix for this is to warm up the
magnet and replace or realign those support rods, likely a 10-14 day
process at best. The nice part is if you can tolerate this condition for
awhile longer, you can choose the time at your convenience (or least
inconvenience) for the magnet to be down.
Good Luck. Not a nice announcement for a Friday, the 13th !
- Alan O.
At 4:45 PM -0400 8/13/99, Miriam Uemi, Sao Paulo, Brazil? wrote:
> Dear coleagues,
>
> We are asking for help to solve the problem that we have in our lab.
> We have a DPX300 BRUKER and since two months ago we observed that
>the nitrogen consumption increase from 40 liter to 80 liter a week. We
>observed also that in middle of magnet have some ice. We conected the vacunn
>system during three weeks but it was not enough to solve the problem.The
>helium consumption is normal (about 1% for 3 days) .
> Someone who can help us please send us a e-mail with suggestions.
>\ Thank you very much
> Best Regards
>
> Miriam
>
>PS. The normal helium refill is 8 months
>
------------------------------------------------
From Alan Olson, Instrument Engineer
National Institutes of Health, NINDS
10 CENTER DR, Room B1D-317, MSC 1060
Bethesda, Maryland 20892-1060
Phone: 301 496 8139, FAX: 301 402 0119
e-mail: awo@helix.nih.gov, olsonc@cvn.net(Alan)
voice mail: 1 800 952 7951 + when it answers: 68139
------------------------------------------------