Josh,
Every nitrogen dewar I use shares the following characteristics:
Main body of the dewar is non-magnetic.
Casters and wheels are magnetically sensitive.
Gauges are very weakly magnetic (needle jumps near a hand held magnet)
The amount of magnetically sensitive materials in the cylindrical part of the
dewar top is minuscule compared the magnetically sensitive steel in the casters
and wheels. As long as that part is firmly and securely in place, I'd feel
perfectly fine using that dewar around any superconducting magnet.
Ronald Shin
University of Alabama at Birmingham
O'Neal Comprehensive Cancer Center
Central Alabama High Field NMR Facility
> From: main_at_ammrl.groups.io On Behalf Of Josh Kurutz via groups.io
> Sent: Wednesday, October 23, 2024 9:18 AM
> To: main_at_ammrl.groups.io
> Subject: [AMMRL] AMMRL: Liquid nitrogen transport dewars - verifying "nonmagnetic enough"
Hi AMMRL Community. Happy Mole Day!
I'd like your help determining whether a particular liquid nitrogen transport
dewar is safe to use for magnet fills. According to its labeling, it's a model
LhP230 from Custom Biogenic Systems. I'm hoping my question about this dewar
can lead to some more general discussion about identifying liquid nitrogen
dewars that are sufficiently nonmagnetic for us to use.
Key points:
* Our dewar in question is NOT specifically labeled "non-magnetic"
like some others we use
* Applying a strongish non-rare-earth magnet to its main body indicates
the main body is basically nonmagnetic. See video here:
https://uchicago.box.com/s/u4qn83bjy9ywaadj976q7g313itf0716
o The casters and wheels are magnetic, which may not be a problem
o The misc hardware and gauges on top of the dewar feel basically nonmagnetic
o The cylindrical part at the center of the top of the dewar does feel weakly
magnetic, so I wonder what's going on inside (see last part of the video)
* The manufacturer appears to have discontinued this product, since it's
not on their website, and they don't have the user manual or product information
posted online
* A customer service rep (first name only) assured me the main body
is nonmagnetic stainless steel, the casters are magnetic, and the gauges are
magnetic (though they don't feel magnetic to me)
* The user's manual sent by the representative had no information about
its magnetic properties and contained no information about whether it was safe
to use around MRIs or other high-magnetic field environments. So we have no
documentation that declares it is safe in our environment.
-=-=-=-=-=-=-=-=-=-=-=-
Groups.io Links: You receive all messages sent to this group.
View/Reply Online (#1785): https://urldefense.com/v3/__https://ammrl.groups=
.io/g/main/message/1785__;!!PvDODwlR4mBZyAb0!XsQJayrYGVWAtHxcTjCofBxKLvQSLe=
4gz7CMho5mA8EijdwmpJB7URNncQi-Kja7gIgAQlWalj4_rFiOXdqIhSJg$
Mute This Topic: https://urldefense.com/v3/__https://groups.io/mt/109171326=
/7559972__;!!PvDODwlR4mBZyAb0!XsQJayrYGVWAtHxcTjCofBxKLvQSLe4gz7CMho5mA8Eij=
dwmpJB7URNncQi-Kja7gIgAQlWalj4_rFiOXQiA6Amt$
Group Owner: main+owner_at_ammrl.groups.io
-=-=-=-=-=-=-=-=-=-=-=-
Received on Wed Oct 23 2024 - 08:23:05 MST