Hi Scott,
thanks for asking. People have not really elaborated on this much but I think
this is reasonable… Here’s my take. In addition to the fills
and transfers themselves (liquefier to dewar (QT) then dewar to magnet: 1-2 hours),
QT recommends to do these tasks regularly:
Daily:
-Operation Data logging
-check for abnormal noises or vibrations
-Check for frosting on Vac. Spaces
-Check for inlet outlet pressure
Weekly:
-Check for leak tightness
-Check Transducer readings for accuracy
-Check for cooling oil level
-Cooler: check the filter mat
-Check N2 level
-check transducers and temperature sensors
Monthly:
-check electrical wiring and connections
-clean the cooler
-check air filter
-clean filter mat
-check setpoints
-check gauges for functional readings
-Purge dewar level sensors
-Check transducers and Temp sensors
-Check coldhead compressor pressures
Yearly
-check system setpoints
-change filter mat
-maintain drive belt
-change air filter
-change oil filter
-change oil separator cartridge
-check safety relief valve
-check safety shut down functions
-check cooler or leaks
-maintenance heat recovery system
-replace filters
-regenerate purifier
-replace purifier absorbant
-Replace inline drier
I am quite unfamiliar with all this and don’t know what most of these
mean. But it certainly sounds like someone in the lab should integrate many
new tasks in their daily routine.
Best
Christophe
> From: main_at_ammrl.groups.io On Behalf Of Smith, Scott K
> Sent: Monday, February 26, 2024 21:14
> To: main_at_ammrl.groups.io
> Subject: Re: [AMMRL] "bag-less" helium-recovery
Hi Christophe,
Thank you for asking and compiling information about this question. Can
you elaborate on the 4-5 hours of maintenance? That sounds like a lot!
Cheers,
Scott
Scott K. Smith, Director of NMR Spectroscopy
The University of Texas at Austin | Chemistry | 832-294-1928 | utexas.edu
> From: main_at_ammrl.groups.io On Behalf Of Fares, Christophe
> Sent: Monday, February 5, 2024 2:35 AM
> To: main_at_ammrl.groups.io<mailto:main_at_ammrl.groups.io>
> Subject: Re: [AMMRL] "bag-less" helium-recovery
Dear AMMRLers,
I received a lot of helpful information about the “bag-less + medium
pressure storage” solution for He recovery. I thought I could summarize
here it for everyone. (note: I was mainly looking for important different to
the (seemingly) more widespread “balloon” strategy.)
I got replies from Halifax, Alberta, Syracuse, Guelph, Nebraska, Virginia,
McGill, Columbia, Oklahoma, North Carolina, Memphis who all have or plan to
have a bag-less setup either from Quantum Technologies (QT) or Quantum Design (QD).
All those replies are from North America which proves that this solution is
not so widespread in Europe (although it might reflect a North American bias
of the ammrl?).
So here are some my take-home messages:
-The customer satisfaction is generally high throughout…
-“works well”, “happy”, etc.
-Each NMR lab is unique and the companies will help find customized solution
-Friendly support although sometimes spotty and slow.
-Although companies states recovery potential up to 95%, the actual recovery ranges from 65-92%.
-The main advantages are:
-smaller footprint,
-less expensive,
-less contamination,
-recovery dewar=fill dewar.
-Some disadvantages:
-liquefier runs 24/7,
-lower recovery,
-the “medium pressure” compressor/storage can reach its limits during fast/long fills,
-one person mentioned NMR measurement instabilities because magnets sense back-pressure.
-Other things to pay attention to (not sure these are disadvantages compared to the balloon system):
-patience requires! long learning curve to get optimal recovery!
-requires at least 4-5h of maintenance work per week.
-special attention for pumped magnets (by-pass during fills to avoid alarms?)
-get a He-leak detector! (Suggested: https://www.restek.com/p/28500
-carefully plan your magnet boil-off hook-ups (by knowledgeable people) to
avoid back-pressure instabilities
That’s pretty much it. Thanks to all who took the time to share their experience!
Best regards
Christophe
> From: Fares, Christophe
> Sent: Sunday, January 28, 2024 21:09
> To: main_at_ammrl.groups.io
> Subject: "bag-less" helium-recovery
Dear Community,
I was wondering if there is anyone out there willing to share their experience
with the He-recovery systems like the one from Quantum Technologies (Picasso/
“All-metal”) ---- or similar? --- which have the characteristic
feature that they works without a “balloon” to collect He.
Instead, the He boil-off is directly purified and re-liquefied. In case of high
flow (eg. during fills), a compressor switches on and stores excess flow to a
medium pressure container for later recovery. The advantages are the smaller
space requirements and the helium reaching the purifier less contaminated.
But perhaps there are obvious downsides which I am not seeing, especially since
this solution does not seem to be widespread.
Best regards
Chris
---------------------------------------------------
Christophe Farès, Ph.D.
---------------------------------------------------
NMR Department/NMR Abteilung
Max-Planck Institut für Kohlenforschung
Kaiser-Wilhelm Platz 1
45470 Mülheim an der Ruhr
Tel: +49 208 306 2130
E-mail: fares [a] mpi-muelheim [.] mpg [.] de
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