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Dave,</div>
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That change was made in an attempt to stabilize nitrogen flow for Hall C, in retrospect it did not appear to give much if any benefit.</div>
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-Chris<br>
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<div id="divRplyFwdMsg" dir="ltr"><font style="font-size:11pt" face="Calibri, sans-serif" color="#000000"><b>From:</b> Esr-users <esr-users-bounces@jlab.org> on behalf of kashy@jlab.org <kashy@jlab.org><br>
<b>Sent:</b> Tuesday, August 11, 2020 4:00 PM<br>
<b>To:</b> esr-users@jlab.org <esr-users@jlab.org>; hallb-engineering@jlab.org <hallb-engineering@jlab.org>; Nicholas Sandoval <sandoval@jlab.org><br>
<b>Subject:</b> [Esr-users] [New Logentry] Hall B Torus and DBX Nitrogen System</font>
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<h1 class="x_node-title" style="font-size: 1.6em;"><a href="https://logbooks.jlab.org/entry/3825052" rel="bookmark" style="text-decoration: none;">Hall B Torus and DBX Nitrogen System</a>
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Lognumber <a href="https://logbooks.jlab.org/entry/3825052" class="x_lognumber" style="text-decoration: none;">
3825052</a>. Submitted by <a href="https://logbooks.jlab.org/user/kashy" style="text-decoration: none;">
kashy</a> on <time datetime="2020-08-11T15:56:10-0400"><a href="https://logbooks.jlab.org/entries?start_date=1597172170&end_date=1597179370&book=HBLOG&book=HBTORUS&book=CLOG" style="text-decoration: none;">Tue, 08/11/2020 - 15:56</a></time>.
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Kashy</td>
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<p>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.
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<p>The heater power is 2kW so 30% is 600W or 3g/s of LN2<br>
3g/s is equal to 320 liters/day or 85 gallons/day<br>
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$.</p>
<p>Something to keep in mind!</p>
<p>If the system becomes unstable we may have to review this change, but it worked for years with the heater min at 0...</p>
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