Hi,
I can only second Mike's assessment - please URGENTLY check all pressures and
valves of your helium recovery system (not clear what kind of recovery is
attached), especially magnets above 10 T are quite unforgiving regarding
overpressue, you may be about to quench your magnet!
Cheers, good luck,
Bert
> Am 30.09.2024 um 18:30 schrieb Michael Groves via groups.io
>
> Based on the sweating I see on the helium turret, there might not be much
> to do other than a rebuild. If the magnet vacuum is going bad you can try
> pumping on the magnet without doing a rebuild but that's often just a band-aid
> approach if it does work. Is there moisture or ice on other places on
> the magnet?
>
> It's usually a good idea to check o-rings in these situations--they do fail
> and get lost, and the one on the fill port gets more wear than the rest do.
> I've also seen the ones around the helium sensor fail.
>
> And that seems like a lot of bubbles to see for a helium leak around there.
> Usually I'm used to seeing little pinhole leaks that might bubble a bit,
> or you might have to track down with a leak detector. I'm not sure I'd expect
> that amount of bubbles unless something was under some amount of pressure.
> You've got #heliumrecovery in the subject line of the email--is this magnet
> connected to a recovery system? And are all the valves to that system in
> the appropriate positions? There was one case I know of where the wrong
> valves got closed at the wrong times and it allowed the pressure inside the
> magnet to get higher than normal.
>
> Cheers,
> Mike
>
> On Monday, September 30, 2024 at 09:43:10 AM MDT, Hla Win wrote:
>
>
> Hello Everyone,
> I hope all are well on your side. We have a 500MHz Oxford 22-year-old magnet
> that is leaking LHe. Picture attach. The normal LHe boil-off is 5 cc/h, and
> the average loss is 0.43%, about 23 mL/h. LHe fill is every 90-100 days. It
> uses about 45-50L the most. We’ve lost LHe this week 4x higher than
> normal. You will see bubbles around the base, by the transfer port, by the
> little "black" seal. If you know of anyone who repair magnet, please let me
> know. In the meantime, I would appreciate any recommendations on what I should
> do to minimize the loss.
>
> Thank you.
>
> Hla Win
> Organic & NMR Lab Coordinator
> Department of Chemistry https://chemistry.wwu.edu/
> Western Washington University
> 516 High Street, Bellingham WA 98225
> winpiah_at_wwu.edu <mailto:winpiah_at_wwu.edu> | 360-650-2261 <>
>
>
> <500MHz magnet leak.jpg>
>
>
> <500MHz magnet leak.jpg>
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