Hi Cecile,
We have a vacuum-jacketed LN2 line running from the bulk tank into the lab.
We then connect our fill hose to transfer LN2 directly into the magnets. It's
very handy!
Safety: Our NMR lab already had O2 sensors connected to an alarm/strobe at
the entry doors and to our Campus Safety Office. Our standard NMR training
includes cryogen safety and what to do if there is an O2 alarm.
Flow rate/pressures: Our LN2 bulk tank is at 120 psi (it’s also used for
N2 gas). An Adjustable Pressure Phase Separator (APPS) unit steps the pressure
down to 23 psi for liquid service. Because the APPS is essentially a 100-150 L
Dewar, it replenishes periodically from the bulk tank. During replenishment,
the flow rate and/or pressure increases a bit - I would say 30 psi. No issues
with the magnets, but if I would prefer a dedicated 23 psi bulk tank for liquid
service.
Leaks: None.
Other points: We use the vacuum-jacketed line about once a week, and it needs
about 20 minutes before any liquid comes out. So, we do all our LN2 fills on
the same day. Our LN2 supplier does offer a "Cryovent" that keeps the vacuum-jacketed
line cold at all times (at the expense of liquid nitrogen), but we do not use
that option.
Best,
Sameer
--
Sameer Al-Abdul-Wahid, Ph.D. | Manager
Nuclear Magnetic Resonance Centre | University of Guelph
50 Stone Rd E | Guelph, ON | N1G 2W1 | CANADA
519-824-4120 Ext. 58914 | s.wahid_at_uoguelph.ca<mailto:s.wahid_at_uoguelph.ca>
> From: main_at_ammrl.groups.io <main_at_ammrl.groups.io> on behalf of Cecile Le Duff <c.s.leduff_at_bham.ac.uk>
> Date: Wednesday, June 7, 2023 at 09:40
> To: main_at_ammrl.groups.io <main_at_ammrl.groups.io>
> Subject: [AMMRL] Liquid nitrogen "on tap" inside an NMR room: your experience
Dear colleagues,
As part of the design of a new Chemistry building, we are looking into getting
some liquid N2 "on tap", directly into the NMR room.
I am only aware of one NMR lab so far having implemented this (aside from biology
colleagues with small rooms, purpose-built for decanting) so I thought I'd pick
the brains in our community.
1/ Do you have such system installed and what do you use it for (decanting into
open top dewars, filling magnets, etc…)?
a/ What are your safety features?
b/ Do you have specific training requirements for all coming into of the NMR facility?
c/ if you are filling magnets with the system, are the flowrate/pressure reliable?
d/ have you had any leaks?
2/ If you have considered such a system and have decided NOT to implement it, why did you decide against it?
a/ price?
b/reliability?
c/resistance from Safety Services?
d/other
Any experience/comments you shared on this will be greatly appreciated. Thank you!
I'll summarize the responses for the benefit of the group/archive.
Kind regards,
Cecile
------------------------------------
Dr Cecile S. LE DUFF
NMR Experimental Officer
School of Chemistry
University of Birmingham
Edgbaston B15 2TT
UK
Tel. + 44 (0) 121 414 4419
c.s.leduff_at_bham.ac.uk
------------------------------------
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Received on Thu Jun 08 2023 - 05:31:16 MST