Author Topic: REALLY! High Pressures  (Read 132 times)

Alan

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REALLY! High Pressures
« on: January 06, 2019, 04:37:27 PM »
As our resident expert, Bob Sterne, recently pointed out, Boyle’s law ( the pressure [P] of a gas is inversely proportional to the volume [V] ) only works with an “ideal” gas. In the real world, at some point ( depending on temperature, and the gas in question [helium, nitrogen, etc.] ), the law falls apart. In other words, doubling the pressure doesn’t cut the volume in half! This fact is important to remember.

A few months back, a prototype airgun was proffered which used a 7,500 PSI (≈520 bar) air supply. Air (gas), in this case, was the air we breathe. Had the airgun used helium or nitrogen, it might have been more interesting.

In case you missed the point here, you need to ask yourself a question. All else being equal, how many more shots could you take, using a tank pressure of 7,500 PSI (≈520 bar), versus one using 4,500 PSI (310 bar)? Now don’t be surprised at the answer! Depending on the tank volume, using the air we breathe, perhaps only 4 to 6!

What bothers me the most, is that some PCP airgun enthusiasts have a death wish! I’ve actually seen past-due (recertification) SCBA tanks filled to 5,000 psi (345 bar), and no over-pressure relief valve in sight! If one of these tanks let loose, the result could cause fatal injuries to anyone close by.

Imagine what would have happened, if this was the case in this video?
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I shudder to think!


  • Roswell, New Mexico
Alan

I have an Omega compressor. If you're a fellow Guild member, and you pass through Roswell, NM, I'll fill your portable tank as a courtesy.

Nicesurprice

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Re: REALLY! High Pressures
« Reply #1 on: January 07, 2019, 05:51:38 AM »
We can fill up to 420 Bar.
Need to find a bottle witch can handle it 😂
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