Hello,
We have just installed a Medium pressure Helium recovery system by Quantum
Design, QD. We had recently transferred 119 liters of liquid into our 600
MHz magnet. Our Renner helium compressor seems to be able to keep up with
the boiloff during liquid helium transfer. We are told by the installers to
keep the oil temperature of the compressor below 60C. I would love to hear
about your experience with a similar system.
We had chosen the QD system with 3 X '1000-Liters' storage tanks because the
contamination level is much lower than the "bag' system. So far it seems to
be a robust system. We opted for a mechanical backpressure controller and
the pressure in the magnet do goes through cycles of pressure fluctuations
of less than 0.3 inches of H2O every 90 seconds. No impact on NMR data has
been detected so far. The tanks have 29" diameter and 92" high.
Best regards
Yong-Wah Kim,
________________________________
> From: main_at_ammrl.groups.io on behalf of Sebastian Kemper via groups.io
> Sent: Tuesday, July 29, 2025 8:30 AM
> To: 'main_at_ammrl.groups.io' <main_at_ammrl.groups.io>
> Subject: [EXTERNAL] [AMMRL] Helium recovery - bag size
Hello everyone,
I would like to modify my helium recovery system so that I can collect helium
during the filling procedure. Due to the relatively limited space, I have a
few questions about balloon size and compressor performance and I would be
very grateful for any experience from colleagues so that I can purchase the
right equipment.
- How much helium will be produced with a fill of 80-90 liters? I calculated
for 80 liters with a fill loss of 15% that max. 16 m³ will be released
during the fill (assuming the cold replaced gas will warm up from 4 K to 298 K).
What are the real numbers? Are there any empirical values?
- I probably only have space for a balloon of 10-12 m³. Do you have a setting
where the compressor starts during filling and compensates for a balloon that is
‘too small’? A colleague told me, that it is possible, but I don't want to
miscalculate and it would be very helpful to hear about other cases. If you have
such a setting, what size balloon do you have? What is the compressor's flow rate?
At what percentage of the balloon volume does the compressor activate?
Best regards,
Sebastian
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Received on Tue Jul 29 2025 - 17:48:59 MST