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-   -   Nitrogen for tires.. (https://vansairforce.net/community/showthread.php?t=17400)

pierre smith 05-06-2007 05:44 AM

Underwater??
 
Greg, (re: reverse flow),
Is that why tires on submerged trucks and cars remain inflated for many years? We dove on shipwrecks in Truk lagoon a few years back and the tires on the trucks in the ship's holds still looked inflated.

Thanks,

airguy 05-06-2007 09:34 AM

Couldn't say for sure, I don't have any experience with that. It stands to reason that you're looking at two effects, though. First, higher ambient pressure underwater is going to slow the rate of leakage (lower delta-P) through the rubber, so they will stay inflated longer. Second, the trucks are going to be considerably more bouyant in water than in air - so you've got a lot less weight on those tires, allowing them to "look" inflated even at relatively low pressure.

Also - truck tires are usually inflated anywhere from 60 to 100 psi, so they will take longer to bleed down to something that looks "flat" than a standard 30 psi tire inflation, and new rubber most likely will last longer in any case.

LR60 01-25-2012 07:46 PM

Way off topic but...HELP
 
Since all you mechs where talking about nitrogen here....

Where can I buy a high pressure nirtrogen bottle service adapter?

The little 90 degree screw on adapter you attach to High Pressure bottles, its made to hand tighten only?

Need a couple fast.

Thanks

Walt 01-25-2012 08:35 PM

You need a high pressure nitrogen regulator, then you can adapt that to whatever hoses/adapters you like. I think HF carries a tire fill kit for this.

LR60 01-26-2012 07:16 AM

I
 
I have the bottle, hose and regulator. I just need that common screw on fitting to hook up to shrader fill valve.

Just can't seem to find one.

Walt 01-26-2012 07:25 AM

Spruce has them: http://www.aircraftspruce.com/catalo.../gooseneck.php

If you're just filling tires you can use a standard tire chuck.

LR60 01-26-2012 07:28 AM

Yep
 
Thats it,

I could not find it on there website lastnight

Thanks Walt!

BillL 01-26-2012 12:55 PM

N2 Won't Support Combustion
 
I think "jarhead" had it right. Heavy equipment tires use N2 because they get hot and release combustible gasses which combines with the oxygen (if it was air) and explodes. On highway trucks can do the same if they end up underinflated then suddenly light off. Other things such as presence of oils, hydraulic etc, can also autoignite (rapid exothermic oxidation) as pressures are high also. Compression heating during landing in struts, and the like, with hydraulic accumulators etc. Reference diesel compression/combustion.

All the remainder of the N2 "reasons" and "benefits" sounds like an active marketing imagination to sell something, but that is just my opinion. :D

I will be using low leak tubes.

Av8torTom 01-26-2012 04:12 PM

Right on Bill
 
Let's put a end to this silly idea. The difference between a nitrogen atom and an oxygen atom is one proton and one electron (and maybe a neutron or two). Both form doublet molecules (N2 and O2). There can be NO difference in diffusibility of the two molecules through the rubber. If anything, nitrogen is the smaller of the two atoms. I think the only benefit is the non-oxidative nature of N2


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