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Illegal bottle!?!

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LMNOP

LMNOP

Member
Jul 7, 2021
394
245
Southern United States
In which situation(s) is/are the following physically possible?

  • As ambient temperature increases the interior pressure in the bottle reduces.
  • As ambient temperature decreases the interior pressure in the bottle increases.
  • As elevation increases, and temperature remains constant, the interrior pressure in the bottle reduces.
  • As elevation decreases, and temperature remains constant, the interrior pressure in the bottle increases.

In all cases of the above, will it happen equally with:

  • 300cc air cylinder
  • 480cc air bottle
  • 90cu-in air bottle
  • 60 minute SCBA bottle

I am told that the above does not adhere to law. Does anyone have any experience regarding the above I have a CF bottle which is suspect and appears to not be in adherence with certain laws.


 
I think you have your Temps reversed. Rise in temp will increase internal psi. Lower temp will decrease internal psi. What laws are you questioning? Physics or legal? Legal for transportation would mean DOT certification and or hydro tested every 5 years. If your bottle is Chinese it may not be DOT certified and dive shops won't touch it. But you can get your own compressor and fill it yourself. Dive shops won't fill bottles without safety certifications , it's a liability issue if your bottle fails.
 
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I'm totally lost as to your question, as it begins with physics/law, in which case no bottle can avoid it, but you appear to asking about legal law?

The top two you have backwards. temperature increase raises pressure.

As for altitude, the absolute pressure in a sealed container will remain constant, but as you raise the altitude, the relative pressure (difference between inside the container and outside) increases.

In all cases I believe it is percentage of the volume, so each container will have the same amount of leeway.


 
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Well if we are going to get specific the air we put in our tanks is 78% nitrogen 21% oxygen .9% argon and .1% other. It is compressed atmospheric air and not illegal to put in a tank for use in any country that I am aware of. I would recommend that if you are concerned about the condition or safety of the tank you plan to use then get it hydro tested before you put hpa in it.
 
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In my line of work, when I see something that seems to be defying the laws of physics or electricity, I always step back and check my assumptions. We often assume our gages and instruments are working correctly, when in fact they may not be. How are you measuring pressure and temperature? Have you tried an additional gage or thermometer, to verify the accuracy of the first? Give us more information, before our curiosity drives us mad!

James 
 
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WHEN YOU COMPRESS AIR THE AIR GETS HOT. THE HEAT CAN BE REMOVED BEFORE IT ENTERS THE BOTTLE BY COOLING THE "TRANSPORTATION PIPING: FROM THE COMPRESSOR CYLINDER TO THE BOTTLE, IF ENOUGH HEAT IS REMOVED FROM THE COMPRESSED AIR DURING IT'S TRIP FROM THE COMPRESSOR TO THE BOTTLE THEN IT MIGHT BE POSSIBLE TO HAVE THE BOTTLE BOTTLE BE AT ROOM TEMPERATURE. ARE YOU SOAKING YOUR CARBON FIBER BOTTLE IN ICE WATER BATH? I CAN'T BELIEVE YOU CAN DEFY THE LAWS OF PHYSICS AND ALL MY EXPERIENCE WITH COMPRESSED GASSES INCLUDING OUR BREATHING AIR HERE ON PLANET EARTH. YOU HAVE LEFT OUT SOME CONDITIONS ; WHAT KIND OF BOTTLE. IS THE BOTTLE AT ROOM TEMPERATURE OR FREEZING OUTSIDE, HOW LARGE IS THE VALVE ON THE BOTTLE AND DID YOU OPEN IT FULLY, WAS THIS JUST AFTER FILLING SAID BOTTLE. WHEN A COMPRESSED GAS IS ALLOW TO ESCAPE IT EXPANDS AND RAPIDLY COOL LIKE YOU BLOWING OVER A CUP OF HOT COFFEE, YOUR BREATH EXPANDS AND REMOVES SOME HEAT FROM THE COFFEE. IT MIGHT BE POSSIBLE FOR THE FRICTION OF THE AIR MOVING THROUGH THE VALVE PRIOR TO IT EXPANDING JUST OUTSIDE THE VALVE TO HEAT THE VALVE. MIGHT, BUT I HAVE NEVER SEEN THAT WARM THE BOTTLE. AND HAVE YOU BY CHANCE LEFT OUT THAT YOU ALSO HAVE A COMPRESSED GAS BOTTLE SOMEWHERE IN ALL THIS. ALONG WITH THE COMPRESSOR. YOU MUST UNDERSTAND YOU CANNOT BREAK THE LAWS OF PHYSICS ( BOYLE AND CHARLES). YOU CAN VIOLATE DEPARTMENT OR TRANSPORTATION LAWS WHEN SHIPPING THE PRESSURIZED GAS IN AN UNSAFE MANNER ENDANGERING THE GENERAL PUBLIC. SOMEHOW YOUR METHOD OF MAKING OBSERVATIONS OF WHAT IS OCCURING ARE CAUSING YOU TO HAVE THIS CONFUSION. OR PERHAPS YOU ARE SIMPLY MESSING WITH US. I HAVE TROUBLE BELIEVING YOU ARE CONFUSION THE " LAWS" OF PHYSICS WITH FEDERAL, STATE AND LOCALLY ENFORCED LAWS. THE LAWS OF PHYSICS MEANS THAT IF YOU COMBINE HYDROGEN GAS AND OXYGEN GAS IN A LEAK PROOF CONTAINER UNDER NORMAL ATMOSPHERIC CONDITIONS IT WILL ALWAYS FORM WATER H2O AND ANY LEFTOVER GASSES WILL SIMPLY DISSIPATE. 
THAT IF SUN LIGHT HITS YOUR BODY IT WARMS YOU ON A 60 DEGREE DAY THIS LAW IS UNBREAKABLE HERE UNDER NORMAL ATMOSPHERIC CONDITIONS A LAW OF PHYSICS IS THAT COMPRESSING GAS WILL HEAT THE GAS AND THE THERMODYNAMICS LAW SAYS THE CONTAINER WILL ABSORB AS MUCH OF THAT HEAT AND TRANSMIT IT TO THE ATMOSPHERE OUTSIDE THE CONTAINER. THE 4 "SITUATIONS" YOU DESCRIBE NOT POSSIBLE HERE UNDER NORMAL CONDITIONS. THE LAWS OF PHYSICS APPLY TO ALL THE BOTTLE YOU MENTIONED. FEDERAL DOT ENFORCEABLE LAWS APPLY TO ALL THE BOTTLES YOU MENTIONED. IF CAUGHT IN VIOLATION THESE DOT LAWS ARE ENFORCEABLE IN COURT. THERE IS ONLY ONE PENALTY FOR VIOLATING PHYSICS LAW ( IF YOU ARE ABLE) YOU GET THE DARWIN AWARD.
 
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