| Topic: |
Science > Physics |
| User: |
"CWatters" |
| Date: |
24 Aug 2005 01:27:13 PM |
| Object: |
Pressure as a measure of capacity |
If you have a cylinder of compressed gas.. Is the pressure allways a measure
of the amount of gas left in the tank or does the pressure stay constant as
the liquified gas boils off?
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| User: "Uncle Al" |
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| Title: Re: Pressure as a measure of capacity |
24 Aug 2005 02:57:08 PM |
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CWatters wrote:
If you have a cylinder of compressed gas.. Is the pressure allways a measure
of the amount of gas left in the tank or does the pressure stay constant as
the liquified gas boils off?
If you have a cylinder of liquefied gas at constant temperature, its
pressure is consant until the last of the liquid evaporates. You tare
the empty cylinder, fill it, and then weigh it to know its remaining
charge.
A nice touch is an adhesive strip of liquid crystal thermometer.
Cooling by evaporation gives you a visible temperature divide.
--
Uncle Al
http://www.mazepath.com/uncleal/
(Toxic URL! Unsafe for children and most mammals)
http://www.mazepath.com/uncleal/qz.pdf
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| User: "Sam Wormley" |
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| Title: Re: Pressure as a measure of capacity |
24 Aug 2005 01:41:37 PM |
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CWatters wrote:
If you have a cylinder of compressed gas.. Is the pressure allways a measure
of the amount of gas left in the tank or does the pressure stay constant as
the liquified gas boils off?
What about temperature?
http://scienceworld.wolfram.com/physics/IdealGasLaw.html
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| User: "Sam Wormley" |
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| Title: Re: Pressure as a measure of capacity |
24 Aug 2005 02:17:03 PM |
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CWatters wrote:
If you have a cylinder of compressed gas.. Is the pressure allways a measure
of the amount of gas left in the tank or does the pressure stay constant as
the liquified gas boils off?
What about temperature?
http://scienceworld.wolfram.com/physics/IdealGasLaw.html
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| User: "tj Frazir" |
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| Title: Re: Pressure as a measure of capacity |
24 Aug 2005 03:35:50 PM |
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The oxygen for your cutting torch is just compressed.
Your bick lighter is a liquid and it rams liquid up the pipe .
gas constant volumes are thermal and letting the liquid out too fast
will chill the head gasses.
The propane BBQ grill converts to a gas from boil off . OFF the gas
side of the tank from the head.
The water piston 2 cycle 2 cylinder runs water as pistons and adds
liquid oxygen boost to gas air mix at the top dead center.
The water boils so the fuel is backed off as to maintain a boil wile
oxygen boost is direct injected into the steam at 16//1 at top of
compresion stroke.
A smaller tiny cylider fires first to ram the compresion of the larger
cyclinder its in up to 16//1.
600 psi detnation 350 ci at 60 strokes per minute run a sliding vane
rotor 24 dia at 1 inch of vane blocking the flow 100 %.
The inner cam slides down to use the other cyclinder by pushing the
vanes out the bottom insted of out the top .
266 hp 126 mpg ...100 hp 225 mpg
266 hp 77 mpg city 88 cadalac
2500 hp at 200 gal day ship .
up to 1 million hp. might run a vlcc 50 knots.
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| User: "Martin" |
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| Title: Re: Pressure as a measure of capacity |
24 Aug 2005 01:42:06 PM |
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CWatters wrote:
If you have a cylinder of compressed gas.. Is the pressure allways a measure
of the amount of gas left in the tank or does the pressure stay constant as
the liquified gas boils off?
which gas?
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| User: "Paul Cardinale" |
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| Title: Re: Pressure as a measure of capacity |
24 Aug 2005 01:43:40 PM |
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If the tank contains both liquid and gas, then the pressure depends
only on the temperature (look up "vapor pressure").
Once all the liquid is gone, the pressure will decline as gas is
removed.
Paul Cardinale
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| User: "CWatters" |
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| Title: Re: Pressure as a measure of capacity |
24 Aug 2005 04:27:59 PM |
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"Paul Cardinale" <pcardinale@volcanomail.com> wrote in message
news:1124909020.306018.37750@z14g2000cwz.googlegroups.com...
If the tank contains both liquid and gas, then the pressure depends
only on the temperature (look up "vapor pressure").
Once all the liquid is gone, the pressure will decline as gas is
removed.
Thanks for that.
In another forum there is a discussion about testing emergency O2 cylinders
used on aircraft. Before each flight pilots test the system by opening a
valve on the face mask and watching to see if there is a pressure drop. I
guess the question now is... would the O2 in such a tank be liquid or just
compressed?
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| User: "Uncle Al" |
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| Title: Re: Pressure as a measure of capacity |
24 Aug 2005 05:28:22 PM |
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CWatters wrote:
"Paul Cardinale" <pcardinale@volcanomail.com> wrote in message
news:1124909020.306018.37750@z14g2000cwz.googlegroups.com...
If the tank contains both liquid and gas, then the pressure depends
only on the temperature (look up "vapor pressure").
Once all the liquid is gone, the pressure will decline as gas is
removed.
Thanks for that.
In another forum there is a discussion about testing emergency O2 cylinders
used on aircraft. Before each flight pilots test the system by opening a
valve on the face mask and watching to see if there is a pressure drop. I
guess the question now is... would the O2 in such a tank be liquid or just
compressed?
Compressed. Look up oxygen's critical temperature.
--
Uncle Al
http://www.mazepath.com/uncleal/
(Toxic URL! Unsafe for children and most mammals)
http://www.mazepath.com/uncleal/qz.pdf
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| User: "James Copeland" |
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| Title: Re: Pressure as a measure of capacity |
24 Aug 2005 10:10:01 PM |
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"Uncle Al" <UncleAl0@hate.spam.net> wrote in message
news:430CF486.4074BD82@hate.spam.net...
CWatters wrote:
"Paul Cardinale" <pcardinale@volcanomail.com> wrote in message
news:1124909020.306018.37750@z14g2000cwz.googlegroups.com...
If the tank contains both liquid and gas, then the pressure depends
only on the temperature (look up "vapor pressure").
Once all the liquid is gone, the pressure will decline as gas is
removed.
Thanks for that.
In another forum there is a discussion about testing emergency O2
cylinders
used on aircraft. Before each flight pilots test the system by opening a
valve on the face mask and watching to see if there is a pressure drop. I
guess the question now is... would the O2 in such a tank be liquid or
just
compressed?
Compressed. Look up oxygen's critical temperature.
--
Uncle Al
http://www.mazepath.com/uncleal/
(Toxic URL! Unsafe for children and most mammals)
http://www.mazepath.com/uncleal/qz.pdf
Yep. Critical temp. of O2 is 154 K, or -119 deg. C. That would be damn cold
for a fighter pilot environs!
Jim C.
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