[Hallb-engineering] [New Logentry] Hall B Torus and DBX Nitrogen System

kashy at jlab.org kashy at jlab.org
Tue Aug 11 16:00:03 EDT 2020

Logentry Text:
During our controls work, I was looking at the cryogenic system. I found that a heater in the LN2 reservoir has been turned on to 30% of full power on ~Jan 9, 2020. There was no record of why in the logbooks and no update of the PID control spreadsheet. The change was done by putting the minimum position for the heater to 30% so I am slowly stepping it back down to 0. 

The heater power is 2kW so 30% is 600W or 3g/s of LN2
3g/s is equal to 320 liters/day or 85 gallons/day
Current cost of LN2 is 0.25$/gallon so we were throwing away ~ 20$/day does not sound like much, but since Jan 9 approximately 4600$.

Something to keep in mind!

If the system becomes unstable we may have to review this change, but it worked for years with the heater min at 0...


This is a plain text email for clients that cannot display HTML.  The full logentry can be found online at https://logbooks.jlab.org/entry/3825052
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