I'm not a chemist either, but 'air' regular or otherwise, does not hold
moisture !!! This is a vary old notion that, well, doesn't hold any air
(ok, bad pun). A simple demonstration can be had by placing a pan of
water in a vacuum chamber, evacuating the chamber (i.e. no more
'regular' air in it) and the water WILL evaporate. Water vapor is a
gas, just as all other component gasses in the atmosphere. Evaporation
is controlled primarily by energy availability, the vapor pressure
gradient (difference in forces exerted by the 'number' of gas molecules
present on either side of an interface), and water availability.
Using an air compressor to fill tires would simply use ambient
atmosphere pumped under pressure into the tire. This air already has
some water vapor in it (even air over the Sahara has a little water
vapor in it). Using a bottled purified gas (like nitrogen) there is
likely to be no water vapor in the mixture. Thus, less chance for rust.
Same idea for the car capsule enclosure - merely displacing the ambient
atmosphere that already contains some water vapor with a purified gas.
Nothing about air 'holding' moisture. You could probably achieve the
same result with a closed capsule and some humectant (like silica gel or
bentonnite clay). I've seen some capsules with fans that maintain the
inflated bubble, but also probably help to keep the vapor pressure such
that the water vapor doesn't reach a high level in the laminar layer
next to the metal (maintain the mixing kind of idea).
Hope this helps, rather than confuse. But please remember, the air
doesn't really hold mositure !!
Bud Precht
>There is likely some
>validity to the claim regarding the moisture characteristics, since normal
>air would typically contain moisture and pure nitrogen would not (I know
>it's used in waterproof binoculars to purge out all of the moisture).
>
>Also something about nitrogen not holding water as'regular' air does.
Check out the new British Cars Forum:
http://www.team.net/the-local/tiki-view_forum.php?forumId=8
|