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<p class=MsoNormal><span style='font-size:12.0pt;font-family:"Arial","sans-serif";
color:#1F497D'>Pressure from hydrogen generators is low. Accidents I am aware
of happened due to high hydrogen bottle pressure, and failure of regulator (if
this happens, H2 can also very quickly go right through intact piping into the
process tool and out the other end, causing a problem in the exhaust!). So
speed/volume of gas escape is much less from a generator. A Valve Manifold Box
can be used close but downstream of a generator for any distribution to
multiple tools, and that is a place where excess flow sensing and leak
detection around valves in an exhausted enclosure is possible. And you are not
storing any hydrogen with a generator. <o:p></o:p></span></p>
<p class=MsoNormal><span style='font-size:12.0pt;font-family:"Arial","sans-serif";
color:#1F497D'><o:p> </o:p></span></p>
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<p class=MsoNormal><span style='font-family:"Arial","sans-serif";color:#1F497D'>Abbie
Gregg</span><span style='color:#1F497D'><o:p></o:p></span></p>
<p class=MsoNormal><span style='font-family:"Arial","sans-serif";color:#1F497D'>President</span><span
style='color:#1F497D'><o:p></o:p></span></p>
<p class=MsoNormal><span style='font-family:"Arial","sans-serif";color:#1F497D'>Abbie
Gregg, Inc.</span><span style='color:#1F497D'><o:p></o:p></span></p>
<p class=MsoNormal><span style='font-family:"Arial","sans-serif";color:#1F497D'>1130
East University Drive, Suite 105</span><span style='color:#1F497D'><o:p></o:p></span></p>
<p class=MsoNormal><span style='font-family:"Arial","sans-serif";color:#1F497D'>Tempe,
Arizona 85281</span><span style='color:#1F497D'><o:p></o:p></span></p>
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480 446-8000 x 107</span><span style='color:#1F497D'><o:p></o:p></span></p>
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style='color:#1F497D'><o:p></o:p></span></p>
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<p class=MsoNormal><i><span style='font-size:9.0pt;font-family:"Arial","sans-serif";
color:navy'>CONFIDENTIALITY NOTICE: All information contained in or
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"Arial","sans-serif";color:navy'>. <o:p></o:p></span></p>
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color:blue'><o:p> </o:p></span></p>
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<p class=MsoNormal><b><span style='font-size:10.0pt;font-family:"Tahoma","sans-serif"'>From:</span></b><span
style='font-size:10.0pt;font-family:"Tahoma","sans-serif"'>
labnetwork-bounces@mtl.mit.edu [mailto:labnetwork-bounces@mtl.mit.edu] <b>On
Behalf Of </b>Grimard, Dennis<br>
<b>Sent:</b> Wednesday, July 18, 2012 1:37 PM<br>
<b>To:</b> labnetwork@mtl.mit.edu<br>
<b>Subject:</b> [labnetwork] H2 Generators<o:p></o:p></span></p>
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<p class=MsoNormal><o:p> </o:p></p>
<p class=MsoNormal>All:<o:p></o:p></p>
<p class=MsoNormal><o:p> </o:p></p>
<p class=MsoNormal>I have been watching the discussion regarding H2
generators. Although I agree with most of what has been said I worry
about being able to shut off the generator in case of a leak. The
generator does not know that it is delivering into a leak and unless the leak
is detected then the generator will continue pumping to that leak. Adding
detectors is not the solution. H2 detectors are difficult to place such
that they will pick up a leak. Do you add detectors at every possible
leak point? Add in the high velocities of the cleanroom and I hesitate to
change from bottles to generators.<o:p></o:p></p>
<p class=MsoNormal><o:p> </o:p></p>
<p class=MsoNormal>When considering the costs, you also have to consider the
cost of the added detectors … which are not cheap …<o:p></o:p></p>
<p class=MsoNormal><o:p> </o:p></p>
<p class=MsoNormal>Dennis Grimard, Ph.D.<o:p></o:p></p>
<p class=MsoNormal>Managing Director<o:p></o:p></p>
<p class=MsoNormal>Lurie Nanofabrication Facility<o:p></o:p></p>
<p class=MsoNormal>1246D EECS Blding<o:p></o:p></p>
<p class=MsoNormal>1301 Beal Avenue<o:p></o:p></p>
<p class=MsoNormal>Ann Arbor, MI 48109-2122<o:p></o:p></p>
<p class=MsoNormal>(734) 368-7172 Cell<o:p></o:p></p>
<p class=MsoNormal>http://www.lnf.umich.edu<o:p></o:p></p>
<p class=MsoNormal><o:p> </o:p></p>
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