- Magnet Fill with Slow
Pre-cooling
...
We get the best efficiency when the transfers lines from the Liquifier to the magnet are sufficiently cold. There are two main modes (paths) to pre-cool the system: the slow pre-cooling and the fast-pre-cooling as well as a combination of these two modes which allows to reduce the slow pre-cooling time. During the slow pre-cooling we can estimate when the system is cold enough through the behavior of the Tank T temperature. The fast pre-cooling transfers efficiency ar 47-49% which does not allow to fill the magnet entirely using just one Liquifier although higher efficiencies of about 54% can be obtained with the fast pre-cool if the Liquifier pressure is reduced to 3.5 PSI at the expense of near 2 hours (~8L) where the Liquifier is not producing while reaching the set pressure.
Slow pre-cooling:
There could be the extra benefit of the slow filling.
1. Enable the Flow PID control of the Magnet Return Bypass at 65 slm.
...
Proceed to fill the magnet anytime after the transfer lines are cold. The system is sufficiently cold once the Tank T temperature decreases after opening VJVT (about 5 hours). The figure below shows an example of the Tank T behavior during a slow pre-cooling.
Filling:
1. Open the MagRetBypass valve fully by pressing the "Full Open" button on "MagRetBypass_Main.vi" in CCP and wait until you can see it is fully open on the CCP panel. The magnet pressure will start decreasing. The FMR may spike momentarily.
...