IceShark

Oh, come on, nitorgen is not an inert gas. And the pressure is going to go up as it gets hotter and the molecules speed around faster and faster and bump into things like the tire casing and rim.

I'm sure the other guys are right. N is used because it is cheap (that is, afterall, 80% of our air) and you just dry it out. This can be done fairly simple. It is just getting that last few % of moisture out that costs so much. The old 80/20 rule in action.

GCoy924

I've been a casual reader of these forums for about 4 years and this is the most insightful threads I've ever read. If anyone would like to educate themselves further on this subject, I would suggest reading up on "periodic trends."

IceShark

GCoy924, Yeah, I thought it was a joke at first until I started thinking about it a bit.

Hans, what I do is get medical grade O2 for the diving. I've been told that I might be a dope to do this by the supplier since everything comes from the same spigot at the source. It is the transport and distribution that is the problem. What they do is keep better records on medical and test the gas all the way along distribution for contaminents. The better records are like what is done for railcars, aircraft and drugs so if a problem pops up they can chase down all the parts that came from that build. The testing is what it is, but unless there has been a contamination problem the industrial and medical are going to be the same.

Have you ever seen how dive shops charge up tanks? They tell you to not smoke in their area. What a joke. They are pulling air out of their location and the only scrubbing is via an activated carbon filter. Which is probably past its prime. And if they are using an oil lubed compressor who knows what is going to get in if it is worn.

But for the very few times I need O2 for a diver in trouble, I just pop the extra 5 bucks for medical tracked and tested gas. Who cares when their life is at risk for that small amount of money?

pearldrum944

Isn't Helium supposed to be gone by 2010?

IceShark

No, it is a large component in natural gas from Texas. I think it is over 15% but I may be full of $hit on that number as it seems pretty high. It is also in other gas deposits but far under 15%. According to theory He was about 25% of the Universe after the Big Bang. Which seems confirmed by observation of gas clouds. Well, non-dark matter observations. We are like newborn children figuring out what we actually live in.

So we should have He for awhile though it is very stupid to waste it on party balloons.

Hans

Ice: Fully agree, they should be filled with H2
Balloons rise a lot faster and are a lot more fun for the observer.
Friday...

To your post above: The village I live in has a diving school/training center/maintenance shop/...
You dont want to know what compressor they have, the condition of the one in my garage is better.
Separators and filters are OK though, checked twice per year, mandatory regulation. Licence withdrawn if they dont comply.
But if you are really relying on it I would go for the medical grade as well.
After all you can lose a lot but life only once..

TakeCare

Matthew951

Nitrogen is also used in most if not all NASCAR tires as well. I know this becuase my brother-in-law used to work for Compitition tire at MIS. The nitrogen is used becuase its dryer, so its lighter, and also and most of all, becuase it is much easier to control tire pressure. Nitrogen makes the cars run MUCH more consistant track times above regular air. My brother-in-law said the race teams will deflate and re-inflate the race tires 10 or more times with Nitrogen, befor they get to acceptable moisture levels inside the tire.

Hope my two cents helps,

Matt