Hi Steve,
Another possibility is that the vacuum in your LHe transfer was getting soft.
Good luck.
Simon
________________________________
> From: main_at_ammrl.groups.io on behalf of Stephen Prior via groups.io
> Sent: Tuesday, September 9, 2025 6:08 AM
> To: main_at_ammrl.groups.io <main_at_ammrl.groups.io>
> Subject: [AMMRL] How to diagnose helium icing
Hi all, we always have our helium fills on our Bruker Ascend 500 done by an
engineer (historically Bruker, but we've recently switched to BOC). Anyway,
the engineer is here now doing the fill and he's surprised by how slowly it's
filling - he thinks it'll take just over an hour to fill from ~47%. This doesn't
sound like a massively long time to me, and from memory I think it's roughly
the time it has taken in the past.
He's now mentioned potential ice blockage and it's put the frighteners on me.
How would we diagnose an ice blockage? He didn't feel any resistance when he
inserted the stinger - but would he expect to? How far into the dewar does
the stinger go? Is it likely to encounter the blockage if one was present? Is
there anything else I can look out for during the fill to either confirm a
blockage, or to put my mind at rest?
With thanks,
Steve
[University of Lincoln]<
http://lncn.eu/jv
Dr. Steve Prior | Instrument Scientist
College of Science
University of Lincoln. Brayford Pool, Lincoln, Lincolnshire. LN6 7TS
tel: +44 (0)1522 837098 (office) 22082 (NMR lab)
[University of Lincoln]<
https://www.lincoln.ac.uk/>
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Received on Tue Sep 09 2025 - 06:34:42 MST