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We get the best transfer efficiencies when the transfers transfer lines from the Liquifier to the magnet are sufficiently cold. We have tested two modes (paths) to pre-cool the system: the slow and the fast pre-cooling as well as a combination of these two modes which allows us 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 transfer efficiencies are about 47-49% which does not allow to fill filling the entire magnet entirely volume using just one Liquifier although . Nevertheless, 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 nearly 2 hours (~8L) where the Liquifier is not producing while reaching the set pressure. Although the fast pre-cooling has a lower transfer efficiency the procedure could be performed when the magnet needs to be filled immediately and the slow pre-cool hasn't been done because any of the Liquifiers are near full.
The slow pre-cooling has consistently given the higher transfer efficiencies between 56 and 58% but requires long pre-cooling times (~ 4 to 5 hours) with the potential benefit of a slow filling which is still under study. During the slow pre-cooling we can estimate when the system is cold enough through the behavior of the Tank T temperature.
The . The reported efficiency values were obtained by performing the magnet fill from the seam level all the way to the level probe spike.
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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.
Fast pre-cooling:
1. Enable the Flow PID control of the Magnet Return Bypass at 65 slm.
2. Open VJVA/B, open VJVT and close VPC.
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.
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