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<p>Dear all,</p>
<p>We are currently using Argon to test the FTT damged during the
installation. Around 2pm, the test will be finished. But I think
it is better to wait until 5pm, when temperature will get colder.
Nevertheless, if someone wants to attend it and will not be
available at 5pm, we can do it at 3pm.</p>
<p>Let me know if you prefer 3pm. Otherwise, let's meet in the
counting house at 5:00pm.</p>
<p>Kind regards,</p>
<p>Maxime<br>
</p>
<br>
<div class="moz-cite-prefix">Le 10/01/2018 à 11:08, burkert a
écrit :<br>
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<div class="moz-cite-prefix">Maxime,<br>
<br>
See if you can get the people together for a show and tell. I
would be interested in attending.<br>
<br>
Volker<br>
<br>
On 1/10/18 10:18 AM, mdefurne wrote:<br>
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<p>Dear all,</p>
<p><u><b>Before all explanations, I want to emphasize that
Maxence and I are not gas experts. So we are just
explaining you what we did,why we think it seems to be
safe to make another test of the mixing system with
isobutane. We decline any responsability if something goes
wrong and final approval to start using mixing system with
isobutane must come from the JLab staff in charge of it.
</b></u><br>
</p>
<p>Last night with Maxence, we did the following procedure:</p>
<p>- Closed all the valves.</p>
<p>- Closed the manometer for the argon supply.</p>
<p>From this state where everything is closed, we opened the
valve in the rack on the isobutane line supply and then filled
the line from the isobutane bottle to the upstream valve of
MFCs with isobutane. The pressure was about 25psi (cannot be
more precise since the heat tape was ON at 15% at that
moment... when heat tape is warming, pressure is increasing in
the line). <br>
Then we closed the bottle and left the system in this state
overnight, i.e. all the line insulated with heat tape around
at 15% filled with isobutane.</p>
<p>This morning we went to purge the line. To do so, we first
open the relief valve and then we open the one of the valves
allowing to purge with argon the isobutane MFC line. It is
important to first open the relief valve, otherwise isobutane
will first flow in a line which is not insulated and condense
within a few seconds. (you tried it yesterday evening and
relief valve was then spitting liquid and gaz. So 30F with no
insulation will make isobutane condensing quite fast.)</p>
<p>So this morning, only gaseous isobutane was exiting the
relief valve. Apparently it seems that isobutane is not
condensing anymore. And once the relief valve is closed,
pressure in the line stayed at 0 (With liquid in it, I would
expect to have some pressure built in the line). I
nevertheless insist on the "apparently" since the relief valve
is not exactly on the isobutane line.</p>
<p> So, considering all this, I would <u><b>only recommend</b></u>
to start testing the mixing system with isobutane again. But <u><b>final
approval must be given either by a staff of JLab since
this system is JLab responsability.</b></u></p>
<p>If you want a demonstration of the test later today (because
the mail might not be very clear without the rack in front of
you), we can organize it. However, I have not a faintest idea
about what the next test is to ensure that isobutane is
gaseous, except going through one MFC (no need to start using
both immediately and risk to lose both of them).</p>
<p>Finally, 15% for the heat tape seems fine for ~30F. But
temperature will get colder over the week end and next week.
We might consider to run safe, i.e. testing again isobutane
state as soon as we hit a new minimum of temperature.<br>
</p>
<p>Kind regards,</p>
<p>Maxime<br>
</p>
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</p>
<br>
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