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<p class="MsoNormal"><span style="color:#1F497D">Sean,<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"> There are several things that can happen if you get BCL3 line condensation. The first is incorrect gas flow control through an MFC, most (Gas Calibrated) MFC’s are designed to work in the gaseous phase, if
the gas you are flowing condensates into a liquid the MFC loses its ability to properly control. MFC’s measure gas flow using thermal mass flow, if they are calibrated for gas then flowing a liquid through them will give erratic results. The second problem
is insufficient gas supply, if you the gas delivery for the BCL3 contains numerous changes in direction then the possibility exists that you can actually create a trap if the BCL3 condensates to a level that does not permit gas to flow. We have seen this
in installations where the line run actually had a trap built into it and due to temperature differences along the line run, this line would literally stop gas flow due to the condensation building up to a point that it completely blocked the line.
<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"> Here are industry standard designs considerations that are employed for the proper delivery of BCL3 or other low vapor pressure/low vapor temperature gases.
<o:p></o:p></span></p>
<p class="MsoNormal"><span style="color:#1F497D"><o:p> </o:p></span></p>
<p class="MsoListParagraph" style="text-indent:-.25in;mso-list:l0 level1 lfo1"><![if !supportLists]><span style="font-family:Symbol;color:#1F497D"><span style="mso-list:Ignore">·<span style="font:7.0pt "Times New Roman"">
</span></span></span><![endif]><span style="color:#1F497D">Control the temperature of the cylinder. Most installations utilize a blanket that flows coolant through them that is connected to an independent chiller. The temperature of the cylinder is kept
at room temperature or 1 or 2 degrees warmer then room temperature.<o:p></o:p></span></p>
<p class="MsoListParagraph" style="text-indent:-.25in;mso-list:l0 level1 lfo1"><![if !supportLists]><span style="font-family:Symbol;color:#1F497D"><span style="mso-list:Ignore">·<span style="font:7.0pt "Times New Roman"">
</span></span></span><![endif]><span style="color:#1F497D">The gas line itself (and it should be coaxial), should be heated and insulated. The temperature of the gas line and gas panel components should be 10 to 15 degrees warmer then room temperature.<o:p></o:p></span></p>
<p class="MsoListParagraph" style="text-indent:-.25in;mso-list:l0 level1 lfo1"><![if !supportLists]><span style="font-family:Symbol;color:#1F497D"><span style="mso-list:Ignore">·<span style="font:7.0pt "Times New Roman"">
</span></span></span><![endif]><span style="color:#1F497D">The gas line itself should be designed and built to incorporate the following;<o:p></o:p></span></p>
<p class="MsoListParagraph" style="margin-left:1.0in;text-indent:-.25in;mso-list:l0 level2 lfo1">
<![if !supportLists]><span style="font-family:"Courier New";color:#1F497D"><span style="mso-list:Ignore">o<span style="font:7.0pt "Times New Roman"">
</span></span></span><![endif]><span style="color:#1F497D">Minimal changes in direction.<o:p></o:p></span></p>
<p class="MsoListParagraph" style="margin-left:1.0in;text-indent:-.25in;mso-list:l0 level2 lfo1">
<![if !supportLists]><span style="font-family:"Courier New";color:#1F497D"><span style="mso-list:Ignore">o<span style="font:7.0pt "Times New Roman"">
</span></span></span><![endif]><span style="color:#1F497D">Should be located as close as possible to the use point.<o:p></o:p></span></p>
<p class="MsoListParagraph" style="margin-left:1.0in;text-indent:-.25in;mso-list:l0 level2 lfo1">
<![if !supportLists]><span style="font-family:"Courier New";color:#1F497D"><span style="mso-list:Ignore">o<span style="font:7.0pt "Times New Roman"">
</span></span></span><![endif]><span style="color:#1F497D">There should be no traps built into the line, even if run path requires it. This will cause big problems.<o:p></o:p></span></p>
<p class="MsoListParagraph" style="margin-left:1.0in;text-indent:-.25in;mso-list:l0 level2 lfo1">
<![if !supportLists]><span style="font-family:"Courier New";color:#1F497D"><span style="mso-list:Ignore">o<span style="font:7.0pt "Times New Roman"">
</span></span></span><![endif]><span style="color:#1F497D">The line (if possible) should be sloped or designed so that it would naturally drain to the delivery source.
<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"> I hope that helps. Let me know if you would like any more information.<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">Thank you,<o:p></o:p></span></p>
<p class="MsoNormal"><span style="color:#1F497D"><o:p> </o:p></span></p>
<div>
<p class="MsoNormal"><b><span style="font-family:"Arial","sans-serif";color:navy">Craig Cheney<o:p></o:p></span></b></p>
<p class="MsoNormal"><span style="color:navy"><img width="239" height="79" id="Picture_x0020_1" src="cid:image001.jpg@01D5E64E.B47EBCE0" alt="Description: cid:image001.jpg@01C7E19F.47FFBAE0"></span><span style="font-size:12.0pt;font-family:"Times New Roman","serif";color:navy"><o:p></o:p></span></p>
<p class="MsoNormal"><span style="color:navy"><o:p> </o:p></span></p>
<p class="MsoNormal"><b><span style="font-family:"Arial","sans-serif";color:navy">Desk: (608)834-4200<o:p></o:p></span></b></p>
<p class="MsoNormal"><b><span style="font-family:"Arial","sans-serif";color:navy">Fax: (608)834-4299<o:p></o:p></span></b></p>
<p class="MsoNormal"><b><span style="font-family:"Arial","sans-serif";color:navy">Cell: (608)438-8714<o:p></o:p></span></b></p>
<p class="MsoNormal"><b><span style="font-family:"Arial","sans-serif";color:navy"><o:p> </o:p></span></b></p>
<p class="MsoNormal"><span style="font-size:12.0pt;font-family:"Arial","sans-serif";color:#484848;background:white">Aviation in itself is not inherently dangerous. But to an even greater degree than the sea, it is terribly unforgiving of any carelessness, incapacity
or neglect. - Captain A. G. Lamplugh </span><b><span style="font-size:12.0pt;font-family:"Arial","sans-serif";color:navy"><o:p></o:p></span></b></p>
<p class="MsoNormal" style="mso-margin-top-alt:auto;mso-margin-bottom-alt:auto"><b><span style="font-size:10.0pt;font-family:"Arial","sans-serif";color:navy">This e-mail transmission and any attachments to it are intended solely for the use of the individual
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this communication in error, please notify the sender immediately by replying to this message and delete it from your computer.<o:p></o:p></span></b></p>
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<p class="MsoNormal"><span style="color:#1F497D"><o:p> </o:p></span></p>
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<div style="border:none;border-top:solid #B5C4DF 1.0pt;padding:3.0pt 0in 0in 0in">
<p class="MsoNormal"><b><span style="font-size:10.0pt;font-family:"Tahoma","sans-serif"">From:</span></b><span style="font-size:10.0pt;font-family:"Tahoma","sans-serif""> labnetwork-bounces@mtl.mit.edu [mailto:labnetwork-bounces@mtl.mit.edu]
<b>On Behalf Of </b>Rinehart, Sean<br>
<b>Sent:</b> Tuesday, February 18, 2020 8:42 AM<br>
<b>To:</b> labnetwork@mtl.mit.edu<br>
<b>Subject:</b> [labnetwork] BCl3 Condensation<o:p></o:p></span></p>
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<p class="MsoNormal"><o:p> </o:p></p>
<p class="MsoNormal">Hi all,<o:p></o:p></p>
<p class="MsoNormal"><o:p> </o:p></p>
<p class="MsoNormal">I know that BCl3 condensation and line heating have been brought up several times in the past so this seemed like a good place to ask about the consequences of BCl3 condensation. Barring subsequent exposure to moisture is there any permanent
damage to the delivery system, or does it just affect process gas mixture and block gas flow until it evaporates off?<o:p></o:p></p>
<p class="MsoNormal"><o:p> </o:p></p>
<p class="MsoNormal">Also, if the delivery pressure is regulated to below the vapor pressure at the coldest point in the delivery system would that effectively eliminate the risk of condensation?<o:p></o:p></p>
<p class="MsoNormal"><o:p> </o:p></p>
<p class="MsoNormal">Thank you,<o:p></o:p></p>
<p class="MsoNormal"><o:p> </o:p></p>
<p class="MsoNormal">Sean Rinehart<o:p></o:p></p>
<p class="MsoNormal">Assistant Director, Cleanroom Operations<o:p></o:p></p>
<p class="MsoNormal">Yale University<o:p></o:p></p>
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