<html>
<head>
<meta http-equiv="Content-Type" content="text/html; charset=utf-8">
</head>
<body text="#000000" bgcolor="#FFFFFF">
Here are a some things to try;<br>
<br>
You definitely need to eliminate any cold spots in the lines to
prevent condensation. The SS tubing at the inlet and outlet of the
MFC are heat sinks. Heating and insulating the C4H10 MFC outlet
tubing will help with that. The heater tapes on the gas lines should
be powered on continuously, not from the thermostat, but at a low
enough setting to be safe. You may also want to increase the
thermostat set point for the MFC base plate.<br>
<br>
If you have "hot spots" in the lines, you may have areas where the
tape is overlapped or touching itself. The tape must not overlap or
touch itself. In time, this may create an electrical short.<br>
<br>
You could also lower the C4H10 output pressure from the regulator,
this should reduce the condensation temperature of the gas. I would
recommend lowering it to 25 psi as a test.<br>
<br>
George<br>
<br>
<div class="moz-cite-prefix">On 12/15/2017 10:04 AM, Marc McMullen
wrote:<br>
</div>
<blockquote type="cite"
cite="mid:8c79c466-a935-f397-c70c-19984f91ce9e@jlab.org">Hi Todd,
<br>
<br>
If you feel comfortable running the mvt mass flow controllers
manually, it may be worth while to vent the mix 1 c4h10 mfc to
atmosphere and flow Argon (maybe 500sccm) for a few hours. Please
make sure the gas lines are reconnected when you are done, so no
moisture gets into the system over the weekend. Please note if you
see any liquid leak out in your logbook entry, and add
<a class="moz-txt-link-abbreviated" href="mailto:dsg-mvt@jlab.org">dsg-mvt@jlab.org</a> to the additional addresses line so that we can
all share the info.
<br>
<br>
Remember that Argon is not the default gas for the selection, that
button must be manually toggled.
<br>
<br>
Additionally, the Saclay group mentioned heating/insulating the
gas lines from the mfc to the tank. This is not necessary to purge
with Argon, but may help with the c4h10 later.
<br>
<br>
If you have any questions give me a call. I am here until lunch.
<br>
<br>
Thanks,
<br>
<br>
</blockquote>
<br>
<pre class="moz-signature" cols="72">--
George Jacobs
Jefferson Lab (TJNAF)
STE 12
12000 Jefferson Ave.
Newport News, VA 23606
(office) 757-269-7115
(cell) 757-876-0480
(email) <a class="moz-txt-link-abbreviated" href="mailto:jacobsg@jlab.org">jacobsg@jlab.org</a>
(website) <a class="moz-txt-link-freetext" href="https://userweb.jlab.org/~jacobsg">https://userweb.jlab.org/~jacobsg</a></pre>
</body>
</html>