Re: [AMMRL] Quench narrowly avoided? Filling small magnets connected to helium recovery

From: Fulton, Luke via groups.io <fko24003=uconn.edu_at_groups.io>
Date: Thu, 12 Jun 2025 17:00:56 +0000

Hi all,

Update:
Yesterday was the first helium fill since discussing dangerous backpressure
a few months ago. Thanks again to everyone for feedback and advise. I redesigned
the manifold connections and things are now much safer. Still a little higher
than the old days before HRS, but nothing to worry about. May I never again
see liquid shoot out from a fill port. Pictures attached for the before/after.

Key changes:
-repositioned helium check valve
-increased ID on hose barb adapters
-open ball valve day before to relieve pressure
(header pressure jumped ~0.03 psi, triggered the system's larger compressor)
(during fill keep valve open, but as precaution close valve on other magnets
in case of quench)
-track fill progress by monitoring collected exhaust gas (rough estimations
remarkably accurate for 1st attempt)

Kind regards,
Luke


Luke Fulton, PhD
CHEM BLDG R003
NMR Core Facility Director
Unit 3060
COR2E & Department of Chemistry
55 N Eagleville Road
University of Connecticut
Storrs, CT 06279

email: fko24003_at_uconn.edu
(alias): luke.fulton_at_uconn.edu
mobile: (603) 953-5275
________________________________
> From: main_at_ammrl.groups.io on behalf of Fulton, Luke via groups.io
> Sent: Tuesday, April 22, 2025 11:33 AM
> To: main_at_ammrl.groups.io <main_at_ammrl.groups.io>
> Subject: Re: [AMMRL] Quench narrowly avoided? Filling small magnets connected to helium recovery


Hi all,

I'm humbled by the amount of support shared in public and private over the
past few days. There's a general consensus that back pressure is much too
high while filling my magnets since we installed helium recovery. Many of
you offered suggestions and optimizations to help address it, which will
inform my setup and procedures going forward. I'll try to summarize the
discussion's main takeaways. Apologies for anything not mentioned, there's
just too much detail contained in these messages to do it all justice.

-The "usual" fill procedure everyone knows comes from before the days of he lium
recovery. The transition to having it can mean adjusting your routine.

-Helium collection apparatus puts additional back pressure on the magnet.
This is generally inversely proportional to the receiving volume for helium
exhaust. Pressures from bag collection systems are seemingly less harsh
than those with medium pressure storage tanks/cylinders. Check valves in
line with exhaust also increase pressure.

-Pressure within magnet relieves slowly over may minutes rather than a few
seconds. Pulling the stinger "hot" from magnet at end of fill can agitate
the system due to larger pressure differential to atmosphere. Beneficial to
slow down transfer rate and let magnet settle somewhat first. How you approach
that would depend on your fill equipment.

-There are several strategies for tracking fill progress. The ones beyond the
liquid level meter require some setup. Nothing difficult, just a matter of
preparation and record keeping. Pressure gauge directly on magnet exhaust
port. Pressure within header line. Stored pressure within bag/cylinders/MPT's.
There's a lot of room for creativity on this subject.

Kind regards,
Luke

Luke Fulton, PhD
CHEM BLDG R003
NMR Core Facility Director
Unit 3060
COR2E & Department of Chemistry
55 N Eagleville Road
University of Connecticut
Storrs, CT 06279

email: fko24003_at_uconn.edu
(alias): luke.fulton_at_uconn.edu
mobile: (603) 953-5275
Office: (860) 486-4069
________________________________
> From: main_at_ammrl.groups.io on behalf of gregory.wylie via groups.io
> Sent: Monday, April 21, 2025 9:01 AM
> To: main_at_ammrl.groups.io <main_at_ammrl.groups.io>
> Subject: Re: [AMMRL] Quench narrowly avoided? Filling small magnets connected to helium recovery


Hello

There have been lots of good ideas presented already but I would like to throw
out a couple more.

One in the pictures you posted the main flow during a fill would be directly
into the side of the tee. Personally I would redo the tee so the main flow
would go straight and the boil-off gas would be on the side.

Second, make sure that you don't have a restriction somewhere else in the
system. I have seen at least 2 times where a company set up a tank in front
of the pump/compressor and they took the 2 in main line to 1/4 in inlet of
this tank. These incidents were on medium pressure systems. So boil-off
will not be an issue but a fill would definitely be an issue!

Good luck.
Greg
Gregory P. Wylie, Ph.D
NMR Facility Manager
Texas A&M University
Department of Chemistry #3255
580 Ross St.
College Station, TX 77843-3255
gpwylie_at_tamu.edu<mailto:gpwylie_at_tamu.edu>
979.458.0705 (voice)
979.845.4719 (fax)
706.206.0007 (cell)
http://nmr.tamu.edu



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Received on Thu Jun 12 2025 - 10:24:27 MST