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Hi Dave,<br>
<br>
Here is some info for the DC Gas System. These relief valves are
critical path for operation of the gas mixing system for the drift
chambers. Do you have a time estimate for this? We cannot test the
drift chambers until we can mix gas.<br>
<br>
Thanks,<br>
George<br>
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<td>[Dsg-dc] ASME relief valves for the DC gas ASME storage
tanks</td>
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<th align="RIGHT" nowrap="nowrap" valign="BASELINE">Date: </th>
<td>Fri, 11 Nov 2016 14:41:59 -0500</td>
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<th align="RIGHT" nowrap="nowrap" valign="BASELINE">From: </th>
<td>George Jacobs <a class="moz-txt-link-rfc2396E" href="mailto:jacobsg@jlab.org"><jacobsg@jlab.org></a></td>
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<th align="RIGHT" nowrap="nowrap" valign="BASELINE">To: </th>
<td>Dave Meekins <a class="moz-txt-link-rfc2396E" href="mailto:meekins@jlab.org"><meekins@jlab.org></a></td>
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<td><a class="moz-txt-link-abbreviated" href="mailto:dsg-dc@jlab.org">dsg-dc@jlab.org</a></td>
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Hi Dave,<br>
<br>
Please find attached system flow diagram for the DC gas mixing
system. Gas mixing supply pressure at the argon and CO2 pressure
regulators is 200 psi. Gas supply pressure to the inlet of the
argon and CO2 MFCs is 140 psi. Mixed gas pressure in the storage
buffer tanks is maintained 80-100 psi by increasing or decreasing
the gas mixing MFC set points. A pic of the tanks is attached. The
lower pair of 5000gal tanks only have 3 connections, 2 on top and
a drain at the bottom. Both of the upper connections are in use,
so we will need to modify that connection for the relief
connection. The upper pair of 2000 gal tanks has an extra
connection on top that can be used for the relief. In all cases,
green epoxy was used on the connections. I can show you these
tanks and connections if you want.<br>
<br>
Max gas flow rates to the tanks.<br>
With the MFC valve at 100% open max flow is 250 slm N2 equivalent,
using the gas correction factors for argon and CO2, we have the
following maximum flow rates;<br>
For argon 1.39 x 250 = 347.5 slm<br>
For CO2 0.7 X 250 = 175 slm<br>
total of 522.5 slm per pair ( 2 independent mixing systems)<br>
<br>
The MFC failure mode for an inlet overpressure is that the valve
cannot open against the high pressure.<br>
The MFC failure mode for an excessive differential pressure across
it is that the valve cannot open due to the excessive differential
pressure.<br>
<br>
Detailed specifications can be found here, <a
moz-do-not-send="true" class="moz-txt-link-freetext"
href="https://www.mksinst.com/product/Product.aspx?ProductID=1458">https://www.mksinst.com/product/Product.aspx?ProductID=1458</a><br>
<br>
The mixing buffers do not require relief valves. These are 250cc
volume HP filter housings, not ASME, listing 3,000 max pressure on
the body. I can show you one, I have a couple spares in the gas
shed and I also use them in the EEL for gas mixing setups. <br>
<br>
Thanks,<br>
George<br>
<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 moz-do-not-send="true" class="moz-txt-link-abbreviated" href="mailto:jacobsg@jlab.org">jacobsg@jlab.org</a>
(website) <a moz-do-not-send="true" class="moz-txt-link-freetext" href="https://userweb.jlab.org/%7Ejacobsg">https://userweb.jlab.org/~jacobsg</a></pre>
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