Hi Greg and Simon, yes the boiloff has been constant for ever, and not changed
at all. The engineer thinks it took 60 - 80 L, which is about normal, and MICS
is reporting that the dewar is full and the hold time as the full six months.
So if the engineer hadn't said anything I would think that everything was working
perfectly normally and wouldn't be worried.
The engineer has finished now and left, so I can't ask him about his transfer
line, but will talk to him about it during our next fill. Or would it be unwise
to wait until our next fill, and try to find out if there's a problem before then?
Thanks for your help,
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)
________________________________
> From: main_at_ammrl.groups.io on behalf of Sham, Shing via groups.io
> Sent: 09 September 2025 12:44
> To: main_at_ammrl.groups.io
> Subject: Re: [AMMRL] How to diagnose helium icing
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
> 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 - 07:15:50 MST