Michael Hopton Michael at
Wed Mar 22 13:14:42 EST 2006

I would go with Aragon or maybe Legolas :^) 

-----Original Message-----
From: 200q20v-bounces at [mailto:200q20v-bounces at]
On Behalf Of Eric_R_Kissell at
Sent: Wednesday, March 22, 2006 11:45 AM
To: 200q20v at
Subject: Re: Nitrogen?

Re: Gas escaping faster

When we leak check in refrigeration, we use Helium purportedly because
it has a smaller molecule and will leak more readily through very small
Plus it is easy to differentiate from typical air, so we can use leak
detectors.  Keep in mind that in mass manufacturing we are trying to
find leaks that might cause a problem 10 years from now in several
minutes of manufacturing process time, thus the high pressure helium
leak checks.
Hydrogen might leak more readily, but using a flammable gases looking
for leaks has always seemed like a bad idea.  Of course, some
refrigeration systems use flammable hydrocarbon gas as the refrigerant,
but that is a whole other conversation.

If we use the molecule size (location on the periodic table of elements)
as a decision criteria, it would appear that Oxygen (8) might leak less
than Nitrogen (7).  Note that Helium is 2 on the periodic table.

Anyway, to reduce leaking, based on the above criteria, I would suggest
that Aragon (18) is the way to go  ; -)

Food for thought,

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