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<p class="MsoNormal"><a name="_MailEndCompose"><span style="color:#1F497D">Hi Rich,<o:p></o:p></span></a></p>
<p class="MsoNormal"><span style="color:#1F497D"><o:p> </o:p></span></p>
<p class="MsoNormal"><span style="color:#1F497D">I don’t know the type of system you have (dynamic – always pumped, static sections “factory sealed”, custom static or flexible), but the industry standard for “good” vacuum on VJ is ~10 micron cold and 40 micron
warm. If you have a vacuum pump port, you should be able to measure and/or pump down. If you are unable to maintain vacuum, you can identify leaks with He leak checker. If you have some form of getter in the interstitial, it may need to be regenerated (unlikely)…Flexible
stuff is generally replaced.<o:p></o:p></span></p>
<p class="MsoNormal"><span style="color:#1F497D"><o:p> </o:p></span></p>
<p class="MsoNormal"><span style="color:#1F497D">Also worth noting on a system that age: Thermal safety reliefs in the piping should be replaced every 10 years and every 5 years on the ASME pressure vessels.<o:p></o:p></span></p>
<p class="MsoNormal"><span style="color:#1F497D"><o:p> </o:p></span></p>
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<p class="MsoNormal"><b><span style="font-size:10.0pt;font-family:"Arial",sans-serif;color:black">Nicholas Menounos,
</span></b><span style="font-size:10.0pt;font-family:"Arial",sans-serif;color:black">PE, LEED AP
</span><span style="font-size:8.0pt;font-family:"Arial",sans-serif;color:black">(he/him/his)</span><span style="font-size:10.0pt;font-family:"Arial",sans-serif;color:#1F497D"><o:p></o:p></span></p>
<p class="MsoNormal"><span style="font-size:9.0pt;font-family:"Arial",sans-serif;color:black">Assistant Director of Infrastructure<o:p></o:p></span></p>
<p class="MsoNormal"><b><span style="font-size:9.0pt;font-family:"Arial",sans-serif;color:red"><o:p> </o:p></span></b></p>
<p class="MsoNormal"><b><span style="font-size:9.0pt;font-family:"Arial",sans-serif;color:red">MIT.nano<o:p></o:p></span></b></p>
<p class="MsoNormal"><b><span style="font-size:9.0pt;font-family:"Arial",sans-serif;color:black">Massachusetts Institute of Technology<o:p></o:p></span></b></p>
<p class="MsoNormal"><span style="font-size:9.0pt;font-family:"Arial",sans-serif;color:black">77 Massachusetts Ave, Bldg 12-4003<o:p></o:p></span></p>
<p class="MsoNormal"><span style="font-size:9.0pt;font-family:"Arial",sans-serif;color:black">Cambridge, MA 02139<o:p></o:p></span></p>
<p class="MsoNormal"><span style="font-size:9.0pt;font-family:"Arial",sans-serif;color:black">Cell: (508) 932-0938<o:p></o:p></span></p>
<p class="MsoNormal"><span style="font-size:9.0pt;font-family:"Arial",sans-serif;color:black">Office: (617) 253-7234<o:p></o:p></span></p>
<p class="MsoNormal"><span style="font-size:9.0pt;font-family:"Arial",sans-serif;color:black">Email: Menounos@mit.edu<o:p></o:p></span></p>
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<p class="MsoNormal"><span style="color:#1F497D"><o:p> </o:p></span></p>
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<p class="MsoNormal"><b>From:</b> labnetwork-bounces@mtl.mit.edu [mailto:labnetwork-bounces@mtl.mit.edu]
<b>On Behalf Of </b>Harlan, Richard D<br>
<b>Sent:</b> Tuesday, February 16, 2021 4:30 PM<br>
<b>To:</b> labnetwork@mtl.mit.edu<br>
<b>Subject:</b> [labnetwork] Liquid Nitrogen Vacuum Jacketed Line Maintenance Question<o:p></o:p></p>
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<p class="MsoNormal"><o:p> </o:p></p>
<p class="MsoNormal">Greetings All,<o:p></o:p></p>
<p class="MsoNormal">Our facility is now 15 years old and starting to require more preventative maintenance. The vacuum jacketed liquid nitrogen line was showing an increased leak rate for a short period of time. It has since stabilized, but has raised questions
about potential leaks in the system. <o:p></o:p></p>
<p class="MsoNormal">Have any of your facilities experienced this type of problem and what PM’s have you put in place to address the LN2 and vacuum jacketed line integrity?<o:p></o:p></p>
<p class="MsoNormal">Thank you in advance for the feedback.<o:p></o:p></p>
<p class="MsoNormal"><o:p> </o:p></p>
<p class="MsoNormal">Thanks,<o:p></o:p></p>
<p class="MsoNormal">Rich Harlan<o:p></o:p></p>
<p class="MsoNormal">Research Engineering<o:p></o:p></p>
<p class="MsoNormal">Birck Nanotechnology Center | Room 2287C<o:p></o:p></p>
<p class="MsoNormal"><b>Office:</b> <span style="color:#2E74B5">765.494.6697</span> |
<b>Email:</b> <a href="mailto:rharlan@purdue.edu">rharlan@purdue.edu</a><o:p></o:p></p>
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