<html><head><meta http-equiv="Content-Type" content="text/html charset=utf-8"></head><body style="word-wrap: break-word; -webkit-nbsp-mode: space; -webkit-line-break: after-white-space;" class="">Hi Vito. I would posture that failure might have been more likely *in between* the fastening tape locations, where the “heat sinking” of the tape is the worst, and hence the temperature of the heat tape was the highest, yeah? The spiral wrap would have left the tape in intimate contact with the tube over the tape's entire length, thereby minimizing hot spots...<div class=""><br class=""></div><div class="">—Mike</div><div class=""><br class=""></div><div class=""><br class=""><div><blockquote type="cite" class=""><div class="">On Jan 21, 2015, at 12:23 PM, Vito Logiudice <<a href="mailto:vito.logiudice@uwaterloo.ca" class="">vito.logiudice@uwaterloo.ca</a>> wrote:</div><br class="Apple-interchange-newline"><div class="">
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<div class="">Dear Colleagues,</div>
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<div class="">We are experiencing an issue with the heat trace on our Dichlorosilane gas line. The all-welded 1/4" SS line is encapsulated with a 1/2" SS outer containment line which is itself heat traced with a single strand of heat trace that runs the entire length
of the coax assembly. The 120 foot line is insulated as shown in the attached photo. A portion of the heat-trace appears to have failed prematurely (it was installed less than one year ago) and we are wondering if the method of installation may be the cause.</div>
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<div class="">The heat trace was not installed in a spiral fashion around the outer 1/2" tube. Rather it was installed in a straight fashion along its entire length with "heat trace fastening tape" located every four feet or so. A member of my team has suggested that
such a straight rather than spiral installation may have caused hot spots (at the fastening locations) which may have in turn caused the failure.</div>
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<div class="">I would appreciate hearing from the community on this point: Are the heat traces around your low pressure gas lines spiral-wound around the lines or are they installed in a straight fashion and somehow fastened along the entire length?</div>
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<div class="">Other insights/suggestions on the proper heat tracing of gas lines by experts in the field as well as comments on possible causes of premature heat trace failure are very much welcome and appreciated. Thank you.</div>
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<div class="">Regards,</div>
<div class="">Vito</div>
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<div class=""><font class="Apple-style-span"><font class="Apple-style-span" face="Calibri" style="font-size: 14px; "><font face="Calibri,sans-serif" class="">--</font></font></font></div>
<div class=""><font class="Apple-style-span"><font class="Apple-style-span" face="Calibri" style="font-size: 14px; "><font face="Calibri,sans-serif" class="">Vito Logiudice </font>P.<font face="Calibri,sans-serif" class="">Eng.</font></font></font></div>
<div class=""><font class="Apple-style-span"><font class="Apple-style-span" face="Calibri"><font face="Calibri,sans-serif" style="font-size: 14px; " class="">Director of Operations, Quantum NanoFab</font></font></font></div>
<div class=""><font class="Apple-style-span"><font class="Apple-style-span" face="Calibri"><font face="Calibri,sans-serif" style="font-size: 14px; " class="">University of Waterloo</font></font></font></div>
<div class=""><font class="Apple-style-span"><font class="Apple-style-span" face="Calibri"><font face="Calibri,sans-serif" style="font-size: 14px; " class="">Lazaridis QNC 1207</font></font></font></div>
<div class=""><font class="Apple-style-span"><font class="Apple-style-span" face="Calibri"><font face="Calibri,sans-serif" style="font-size: 14px; " class="">200 University Avenue West</font></font></font></div>
<div class=""><font class="Apple-style-span"><font class="Apple-style-span" face="Calibri"><font face="Calibri,sans-serif" style="font-size: 14px; " class="">Waterloo, ON Canada N2L 3G1</font></font></font></div>
<div class=""><font class="Apple-style-span"><font class="Apple-style-span" face="Calibri"><font face="Calibri,sans-serif" style="font-size: 14px; " class="">Tel.: (519) 888-4567 ext. 38703</font></font></font></div>
<div class=""><span style="font-size: 14px; " class="">Email: <a href="mailto:vito.logiudice@uwaterloo.ca" class="">vito.logiudice@uwaterloo.ca</a></span></div>
<div class=""><span style="font-size: 14px; " class="">Website: </span><a href="https://fab.qnc.uwaterloo.ca/" class="">https://fab.qnc.uwaterloo.ca</a></div>
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<span id="cid:57AA8884F626D543B2AE81B075635E98@connect.uwaterloo.ca"><DCS.png></span>_______________________________________________<br class="">labnetwork mailing list<br class=""><a href="mailto:labnetwork@mtl.mit.edu" class="">labnetwork@mtl.mit.edu</a><br class="">https://www-mtl.mit.edu/mailman/listinfo.cgi/labnetwork<br class=""></div></blockquote></div><br class=""><div apple-content-edited="true" class="">
<div style="color: rgb(0, 0, 0); letter-spacing: normal; orphans: auto; text-align: start; text-indent: 0px; text-transform: none; white-space: normal; widows: auto; word-spacing: 0px; -webkit-text-stroke-width: 0px; word-wrap: break-word; -webkit-nbsp-mode: space; -webkit-line-break: after-white-space;" class="">-- <br class=""><font face="Consolas" class=""><span style="font-size: 11px;" class="">Michael P. Young (574) 631-3268 (office)<br class="">Nanofabrication Specialist (574) 631-4393 (fax)<br class="">Department of Electrical Engineering (765) 637-6302 (cell)<br class="">University of Notre Dame <a href="mailto:mike.young@nd.edu" class="">mike.young@nd.edu</a><br class="">B-38 Stinson-Remick Hall<br class="">Notre Dame, IN 46556-5637</span></font></div>
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