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<p>Hi Bob,</p>
<p>I have contacted Steve Rockwood from MKS, I sent him the P&I
diagram and details of the situation. As soon as I here back from
him I'll pass it along.</p>
<p><br>
</p>
<p>Marc<br>
</p>
<br>
<div class="moz-cite-prefix">On 12/20/2017 11:25 AM, Bob Miller
wrote:<br>
</div>
<blockquote type="cite"
cite="mid:359d948c-9f9b-701e-ca0f-512a971f0b50@jlab.org">
<meta http-equiv="Content-Type" content="text/html; charset=utf-8">
<p>Hi Marc,</p>
<p>What did the MFC vendor say about using these MFCs for this
application?</p>
<p>Bob<br>
</p>
<br>
<div class="moz-cite-prefix">On 12/20/2017 11:23 AM, Marc McMullen
wrote:<br>
</div>
<blockquote type="cite"
cite="mid:1982328490.89036.1513786994953.JavaMail.zimbra@jlab.org">
<div style="font-family: arial, helvetica, sans-serif;
font-size: 12pt; color: #000000">
<div>Hi Maxime,<br>
</div>
<div><br data-mce-bogus="1">
</div>
<div>I have been running argon through the c4h10 mfc which was
removed from the mixing system. It is not functioning
properly after hours of purging. We will need to replace it.
I'll contact MKS today to see if they will repair it. We
need to buy at least two more (~$1600 per), because I
believe the mix 1 c4h10 was not acting properly and was
exposed to condensed gas during the same time, although to a
lesser extent. Testing shows that the valve will no longer
seat, so that if there is any pressure (10-15psi) the mfc
will flow 35 - 50 sccm. If I close off the argon valve at
the regulator, the flow bleeds off, so I believe it's
leaking through the internal valve seat. If the mfc is
mechanically isolated from gas, it measures no flow, so the
sensor seems to be ok. So a repair of the internal
components may be the fastest way to have a second perfectly
running mfc (4 week lead time on purchase). <br
data-mce-bogus="1">
</div>
<div><br data-mce-bogus="1">
</div>
<div>The other focus needs to be on insuring the gas will not
condense in the mfc. You should address this with the system
owner (Bob) and tech (Todd) on the best way to keep the gas
> 70degF. Although the mfcs are specified to operate down
to 50F, the gas may condense due to the small amount of
flow. The mfcs are sized correctly. So unless there is an
objection I will request the same size. <br
data-mce-bogus="1">
</div>
<div><br data-mce-bogus="1">
</div>
<div>We may also consider going with an mfc which may have a
better recovery from this kind of issue. I read an article
on a different brand which may provide some solution in the
future.<br data-mce-bogus="1">
</div>
<div><a class="moz-txt-link-freetext"
href="http://www.alicat.com/alicat-blog/products-and-services/liquid-in-a-gas-flow-controller-how-bad-is-it-doc/"
moz-do-not-send="true">http://www.alicat.com/alicat-blog/products-and-services/liquid-in-a-gas-flow-controller-how-bad-is-it-doc/</a></div>
<div><br data-mce-bogus="1">
</div>
<div>Finally, I have requested a status update from the premix
vendor. When he responds I'll forward the info.<br
data-mce-bogus="1">
</div>
<div><br>
</div>
<div><br>
</div>
<div data-marker="__SIG_PRE__">Marc McMullen<br>
Physics Division<br>
Detector Support Group<br>
7738</div>
<div><br>
</div>
<hr id="zwchr" data-marker="__DIVIDER__">
<div data-marker="__HEADERS__"><b>From: </b>"mdefurne" <a
class="moz-txt-link-rfc2396E"
href="mailto:mdefurne@jlab.org" moz-do-not-send="true"><mdefurne@jlab.org></a><br>
<b>To: </b><a class="moz-txt-link-abbreviated"
href="mailto:dsg-mvt@jlab.org" moz-do-not-send="true">dsg-mvt@jlab.org</a><br>
<b>Sent: </b>Tuesday, December 19, 2017 11:26:33 PM<br>
<b>Subject: </b>[Dsg-mvt] News about Isobutane MFC<br>
</div>
<div><br>
</div>
<div data-marker="__QUOTED_TEXT__">Hi Marc,<br>
<br>
What is the schedule for the mixing system? Let me know if
you need <br>
anything or think I could speed up one or two things.<br>
<br>
We are on the last premix bottle. We have to be ready for
January 12th <br>
with either the gas mixing system or premix bottles (when
will the ten <br>
bottles delivered?).<br>
<br>
Cheers,<br>
<br>
Maxime<br>
<br>
_______________________________________________<br>
Dsg-mvt mailing list<br>
<a class="moz-txt-link-abbreviated"
href="mailto:Dsg-mvt@jlab.org" moz-do-not-send="true">Dsg-mvt@jlab.org</a><br>
<a class="moz-txt-link-freetext"
href="https://mailman.jlab.org/mailman/listinfo/dsg-mvt"
moz-do-not-send="true">https://mailman.jlab.org/mailman/listinfo/dsg-mvt</a><br>
</div>
</div>
</blockquote>
<br>
<pre class="moz-signature" cols="72">--
Bob Miller
Hall B Lead Engineer
Jefferson Lab
757 269-7867
</pre>
</blockquote>
<br>
<pre class="moz-signature" cols="72">--
Marc McMullen
Detector Support Group
757-269-7738</pre>
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