Hi,
some hint for the next refill: touch the helium transfer line along the length
line during and after helium filling:
- if it feels well below ambient temperature during refill, the vacuum inside is
really bad, needs pumping (it's normal to be cold around the two bends though,
even a small frozen spot may happen)
- if it gets quite cold after refill (in bad cases you may see some rings forming
where condensation is less, every 15-20 cm or so - these are the internal spacers),
then it's not as bad but re-pumping would be recommended
Other than that I concur with Paulo - doing the transfer slowly can easily
take much longer, plus suffering from increased losses (longer contact time
of the liquid helium in the "warm" transfer line)…
Cheers
Bert
> Am 09.09.2025 um 21:26 schrieb Thomas Eubanks via groups.io:
>
> You have to push the helium fast enough to stay liquid into the magnet.
> Depending on the transfer lines you might have to go up to 3-4 lbs psi. New
> lines with strong vacuum can transfer much lower.
> From: main_at_ammrl.groups.io behalf of falcocobra via groups.io
> Sent: Tuesday, September 9, 2025 1:09 PM
> Subject: Re: [AMMRL] How to diagnose helium icing
>
>
>
> At what pressure is the fill being done? 60-80L taking more than an hour
> does sound a little slow, but if he is doing the fill at 1 psi, that doesn't
> sound out of the ordinary.
> --
> =
> Paulo Falco Cobra | Scientist II - Facility Manager
> NMRFAM <https://nmrfam.wisc.edu/> - University of Wisconsin Madison
>
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Received on Tue Sep 09 2025 - 14:21:47 MST