<div dir="ltr">Iain,<div><br></div><div>good morning. We run nothing for a corrosion inhibitor, or biocide, in either system. We are running a side stream UV lamp. Haven't had any problems with corrosion, or algae in either system. Both are open tank return, so there's essentially zero back pressure, though that shouldn't matter. Polishing is done with a pair of DI tanks that pass about 4-6GPM as needed from the high pressure side, right back into the tank. We measure resistivity on the high pressure side. One system has been operational since 2007 (150GPM), the other (200GPM) probably twice that long. We've had zero problems with either system.</div></div><div class="gmail_extra"><br clear="all"><div><div class="gmail_signature"><div>Dennis</div><div> </div><div>734.647.2055 Ofc</div><div> </div><div>"People can be divided into 3 groups - those that make things happen, those that watch things happen, and those that wonder what happened." Within which group do you belong?</div></div></div>
<br><div class="gmail_quote">On Tue, Sep 15, 2015 at 2:16 AM, Anteney I.M. <span dir="ltr"><<a href="mailto:I.M.Anteney@soton.ac.uk" target="_blank">I.M.Anteney@soton.ac.uk</a>></span> wrote:<br><blockquote class="gmail_quote" style="margin:0 0 0 .8ex;border-left:1px #ccc solid;padding-left:1ex">Denis,<br>
<br>
I'm particularly interested in your comment about polishing the loops to get 1 mega-ohm resistance as we have struggled to do this especially when we dose the system with biocide and corrosion inhibitors. What are you using to polish the system, what inhibitors/biocides do you use and how do these affect the conductivity.<br>
<br>
Regards<br>
<br>
Iain<br>
<br>
Cleanroom Manager<br>
University of Southampton<br>
<br>
Sent from my iPhone<br>
<br>
On 15 Sep 2015, at 00:36, Dennis Schweiger <<a href="mailto:schweig@umich.edu">schweig@umich.edu</a><mailto:<a href="mailto:schweig@umich.edu">schweig@umich.edu</a>>> wrote:<br>
<br>
Vito,<br>
<br>
here at UofMichigan, one of our PCW systems runs about 62.5F (16.9C) with a daily deviation of about 1F. The second runs about 59-60F (15C). It too has a daily deviation of about 1F. For both systems we may see a seasonal deviation of 3-4F as the main chiller plant transitions from "free cooling" to the use of chillers to create cooling water for the campus wide loop. We also "polish" both loops to 1 meg-ohm so that we have a "high resistance" in the RF cooling circuits.<br>
<br>
Dennis Schweiger<br>
University of Mighigan/LNF<br>
<br>
734.647.2055 Ofc<br>
<br>
On Fri, Sep 11, 2015 at 3:47 PM, Vito Logiudice <<a href="mailto:vito.logiudice@uwaterloo.ca">vito.logiudice@uwaterloo.ca</a><mailto:<a href="mailto:vito.logiudice@uwaterloo.ca">vito.logiudice@uwaterloo.ca</a>>> wrote:<br>
Dear Colleagues,<br>
<br>
The process chilled water loop in our cleanroom has consistently oscillated between ~15.4C and ~17.2C over a span of roughly 10 minutes. Our Plant Operations group is looking into the possibility of tightening this up for us by tuning the control sequence. They have asked for guidance on an acceptable specification.<br>
<br>
In light of this I would appreciate hearing from you as to your facility’s PCW temperature target and tolerance. Thank you much.<br>
<br>
Best regards,<br>
Vito<br>
--<br>
Vito Logiudice P.Eng.<br>
Director of Operations, Quantum NanoFab<br>
University of Waterloo<br>
Lazaridis QNC 1207<br>
200 University Avenue West<br>
Waterloo, ON Canada N2L 3G1<br>
Tel.: (519) 888-4567 ext. 38703<tel:%28519%29%20888-4567%20%C2%A0ext.%2038703><br>
Email: <a href="mailto:vito.logiudice@uwaterloo.ca">vito.logiudice@uwaterloo.ca</a><mailto:<a href="mailto:vito.logiudice@uwaterloo.ca">vito.logiudice@uwaterloo.ca</a>><br>
Website: <a href="https://fab.qnc.uwaterloo.ca" rel="noreferrer" target="_blank">https://fab.qnc.uwaterloo.ca</a><br>
<br>
<br>
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