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  #61  
Old 21 January 2014, 10:23 PM
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Hero_Mike Hero_Mike is offline
 
 
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I think I mentioned this a long time ago, but one of the advantages of nitrogen over common air is the lack of moisture in it. Moisture in air can condense, freeze, and cause the bead sealer to separate the tire from the rim, and it can cause steel rims to rust. It may be worthwhile then for winter tires, which are often mounted on cheaper, plain steel rims.
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  #62  
Old 21 January 2014, 11:39 PM
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I've actually filled a small tire straight from a 2000 PSI bottle. I couldn't hold the air chuck on the valve stem above about 100 PSI.

Quote:
Originally Posted by jimmy101_again View Post
Tire explosions aren't exactly common but they aren't unheard of either. http://www.ncbi.nlm.nih.gov/pubmed/1854067
I would think most failures are due to a flaw in the tire or rim but at least some are from over pressurizing (for example to get a bead to seal well). Give the mechanic access to 6000 PSI instead of 120 PSI and who knows what'll happen? A very high pressure source will fill a car tire pretty darn quickly, a mechanic used to 100 PSI could easily blow a tire if he suddenly had 1000 PSI and wasn't careful.

You can get fixed output regulators but most regulators are adjustable. In a shop, with an adjustable regulator, you would need to lock the regulator to keep people from fiddling with it.
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  #63  
Old 22 January 2014, 07:47 PM
jimmy101_again jimmy101_again is offline
 
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Quote:
Originally Posted by BoKu View Post
I've actually filled a small tire straight from a 2000 PSI bottle. I couldn't hold the air chuck on the valve stem above about 100 PSI.
I'm a bit surprised, there should have only been a few pounds of force even at 100 PSI.

I wonder what the pop-off pressure is for locking or screw-on fixtures like this

Edit: I've never had any problem attaching quick connects on pressurized hoses at typical shop pressure of say 120 PSIG.
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  #64  
Old 23 January 2014, 05:54 AM
Alchemy Alchemy is offline
 
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Quote:
Originally Posted by jimmy101_again View Post
I would be very surprised if shoe (foam) manufactures are using "nitrogen" and not referring to bubbles.
The paragraph prior to the first one you quoted discussed the use of gas as a blowing agent, i.e. producing bubbles.

Quote:
Including nitrogen gas
I can google now and find that nitrogen gas is in fact a blowing agent. If you're claiming it was also a blowing agent a year ago, when I made the statements you're responding to, I guess that's probably true, and in any case I'm not in a position to argue.

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I don't see anything wrong with "nitrogen enhanced" fuels since the additives do indeed contain nitrogen.
To paraphrase Judge Judy, don't pee on my leg and tell me it's nitrogen.

I just don't think it's clever to describe chemicals as if they were one particular element they contained. If you hand me a glass of water and tell me it's a glass of hydrogen I reserve the right to roll my eyes. The bonds matter; claiming otherwise just takes you down the "water fueled car" road.

Quote:
You could label a nitrous oxide system as "nitrogen enhanced". Not that that tells you anything.
I'm pretty sure the very suggestion would get me fired for being much too stupid to have my job. Not that any production car would ever use N2O anyway.

Quote:
(Nitrous is used for a completely different reason than are detergents, Nitrous is part of the oxidizer and contributes a heck of a lot of energy to the combustion process.)
Nitrous oxide is used because it's an oxidizer and, unlike oxygen, you can liquify it at room temperature. Its 70F psat is only ~750 psi, so it's similar to a propane tank. No insulation required, minimal degassing. Easy peasy.

Still not great stuff to inject into an engine. Nobody tests (well, not seriously) about what this does to cylinder/block temperatures, and I feel pretty safe stating that no PCM for any car sold in the USA includes N2O injection tables.
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  #65  
Old 23 January 2014, 06:19 AM
Alchemy Alchemy is offline
 
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Quote:
Originally Posted by overyonder View Post
I have a few high pressure regulators in my garage (for welding, carbonating, etc) and all of them have release valve to "dump out" in case the regulator goes on the fritz.
I did a quick survey of the regulators on my instruments; they're all 2-stage regulators that take ~6000 psi gas down to ~400 psi interstage, and the low pressure side maxes out at 150-200 psi. The safety valves are all 400 psi relief valves on the low pressure side. Most of our tubing is rated for around 5000 psi, although our most expensive instruments require 15-40 psi and would probably be catastrophically unhappy at pressures much above 100 psi.

Quote:
Originally Posted by BoKu View Post
I've actually filled a small tire straight from a 2000 PSI bottle. I couldn't hold the air chuck on the valve stem above about 100 PSI.
I can remove and reconnect 1/4" compression fittings for N2 at 45 psi but it's not particularly easy to push the ferrule hard enough into the seat to get the nut to thread. I absolutely could not get a full seal without the lever force of 5 inch wrench.
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  #66  
Old 23 January 2014, 02:39 PM
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GenYus234 GenYus234 is offline
 
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I believe that the force required to seal a compression fitting is about compressing the (brass, copper?) ferrule. BoKu is (I think) talking about fighting the pressure of the gas as the fill hose is sometimes just held on the tire stem.
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  #67  
Old 23 January 2014, 03:40 PM
jimmy101_again jimmy101_again is offline
 
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Quote:
Originally Posted by GenYus234 View Post
I believe that the force required to seal a compression fitting is about compressing the (brass, copper?) ferrule. BoKu is (I think) talking about fighting the pressure of the gas as the fill hose is sometimes just held on the tire stem.
Actually no. For a quick release fitting the pressure you have to apply is proportional to the line's air pressure and the cross sectional area of the seal in the fitting. The cross sectional area though is pretty small, I would WAG it at 1/4" diameter which gives an area of about 0.05in^2 and a force of ~6 pounds at 120 PSIG. The math is similar for a typical tire filling adapter so there should be relatively little force needed to hold it in place even at high pressures.
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  #68  
Old 23 January 2014, 03:46 PM
jimmy101_again jimmy101_again is offline
 
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Quote:
Originally Posted by Alchemy View Post
To paraphrase Judge Judy, don't pee on my leg and tell me it's nitrogen.

I just don't think it's clever to describe chemicals as if they were one particular element they contained. If you hand me a glass of water and tell me it's a glass of hydrogen I reserve the right to roll my eyes. The bonds matter; claiming otherwise just takes you down the "water fueled car" road.
Adds do that. Makers don't use the chemical name since it tells the average Joe absolutely nothing. So a chemist is annoyed because the description is basically worthless, so what? What in an advertisement isn't worthless?

No kidding bonds matter , but again, so what? This is an add trying to differentiate one maker's product from another even though there is zero difference between the two products.
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  #69  
Old 23 January 2014, 04:18 PM
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Quote:
Originally Posted by jimmy101_again View Post
Actually no. For a quick release fitting the pressure you have to apply is proportional to the line's air pressure and the cross sectional area of the seal in the fitting.
A quick release fitting is not the same thing as a compression fitting.
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  #70  
Old 23 January 2014, 04:22 PM
jimmy101_again jimmy101_again is offline
 
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Quote:
Originally Posted by GenYus234 View Post
A quick release fitting is not the same thing as a compression fitting.
You are right, I assumed you were referring to a system in which the fitting is connected / disconnected while the system is pressurized. Compression fittings are never (properly) installed while a system is pressurized. Quick release's are designed to be connected / disconnected while at least one side is pressurized. A tire filling fixture is of course designed to be used when both sides are pressurized.
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  #71  
Old 25 January 2014, 10:53 PM
Alchemy Alchemy is offline
 
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Quote:
Originally Posted by jimmy101_again View Post
Adds do that. Makers don't use the chemical name since it tells the average Joe absolutely nothing. So a chemist is annoyed because the description is basically worthless, so what? What in an advertisement isn't worthless?
I admit I'm finding this exchange confusing. In my post in Feb 2012 I thought I explicitly stated that "nitrogen" was a marketing buzzword at the time. At this point it feels to me that you're "arguing" with me by paraphrasing that post and repeating my own thoughts back to me, but in an angrier tone.

Quote:
Originally Posted by GenYus234 View Post
I believe that the force required to seal a compression fitting is about compressing the (brass, copper?) ferrule.
Stainless steel ferrule, only slightly softer than the treated SS seat. It's not a great comparison but it's the first relevant anecdote I could come up with.

Quote:
Originally Posted by jimmy101_again View Post
Compression fittings are never (properly) installed while a system is pressurized.
Quite right; I had to check a bunch of lines with inert prior to running toxic gases through them, and the N2 shutoff valve was too far away to bother going back and forth. I was lazy and if I had stripped some threads it would've been entirely my fault for being careless.

The ferrules had been bonded to the tube quite a while ago though; I'm not sure it would be possible to install ferrules while the line was flowing.
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  #72  
Old 08 July 2015, 01:30 AM
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Quote:
Originally Posted by BoKu View Post
I've actually filled a small tire straight from a 2000 PSI bottle. I couldn't hold the air chuck on the valve stem above about 100 PSI.
A high school friend of mine who worked at a tire shop was killed when he overinflated a tire at work and it blew up in his face.

Next time you try that, at least warn those around you by announcing, "Hey y'all, watch this!"
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  #73  
Old 16 July 2015, 03:05 AM
JACKLANGHALS JACKLANGHALS is offline
 
 
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Did you ever see a K Bottle valve knocked off at full tank ? Look out !!!!!! I worked at NASA and we used all gases GH2, O2, Helium etc.
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