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Offlinepscyanescens
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Does a empty oxygen cylinder weigh the same full?
    #6481462 - 01/21/07 12:38 AM (17 years, 2 months ago)

I was told that a empty oxygen cylinder weighs the same full. I swear i can tell a difference when i drop off my tanks, and i think the empties weigh less.

However the owner of Apex (my oxygen supplier) in Santa Cruz claims that there is no difference in the weight. I figure he should be credible if he owns the damn place, or runs it whatever.

I still find this hard to believe.


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"With an abundance of Cyanescens... i would never touch another Cubensis again."

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OfflineTheSlapnCapn
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Re: Does a empty oxygen cylinder weigh the same full? [Re: pscyanescens]
    #6481486 - 01/21/07 12:54 AM (17 years, 2 months ago)

Considering oxygen is indeed matter... and all matter has mass... it has to weigh more.

Elementary my boy!


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I promise to live, love, exist, and be, and hope that all life will love to be in existence with me. Also, fuck you.

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InvisibleFlop Johnson
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Re: Does a empty oxygen cylinder weigh the same full? [Re: pscyanescens]
    #6481491 - 01/21/07 12:59 AM (17 years, 2 months ago)

Quote:

pscyanescens said:
However the owner of Apex (my oxygen supplier) in Santa Cruz claims that there is no difference in the weight.




Whaaa? He should know better.

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OfflineKonnrade
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Re: Does a empty oxygen cylinder weigh the same full? [Re: pscyanescens]
    #6481494 - 01/21/07 01:01 AM (17 years, 2 months ago)

full cylinders of gas weigh a hell of a lot more than empty ones. Air is heavier than people think.

If you put a cylinder around the eiffel tower, the air inside would weigh more than the tower does.


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I find your lack of faith disturbing

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OfflineNobodyCares
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Re: Does a empty oxygen cylinder weigh the same full? [Re: pscyanescens]
    #6481497 - 01/21/07 01:03 AM (17 years, 2 months ago)

No. While gases have relatively small densities, there is no way a gas compressed in a tank wouldn't add a qualitative amount of weight.


--------------------
The story goes, or the way that I was told
There was a king that always felt too high and then he fell too low
And so he called all the wise men to the hall
And begged them for a gift to end the rises and the falls
But here’s the thing, they came back with a ring
It was simple and was plainly unbefitting of a king
Engraved in black, it had no front or back
But there were words around the band that said
Just know: This Too Shall Pass


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Offlinepscyanescens
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Re: Does a empty oxygen cylinder weigh the same full? [Re: NobodyCares]
    #6481527 - 01/21/07 01:28 AM (17 years, 2 months ago)

He explains it by saying that determining the atomic weight of oxygen is almost immeasurable. He goes further by saying that if oxygen weighed any considerable amount, then the oxygen above us would be crushing us and making us "feel really heavy" i believe he put it.

My other friend goes to ask if the gas was compressed or liquefied. I don't think it is liquid. Do any welders or fellow glass blowers no if the small industrial tanks are liquid?

I am pretty sure the liquid oxygen tanks are the huge ones that leak a certain percentage everyday, due to the pressure it is under.


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"With an abundance of Cyanescens... i would never touch another Cubensis again."

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Offlinepscyanescens
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Re: Does a empty oxygen cylinder weigh the same full? [Re: pscyanescens]
    #6481536 - 01/21/07 01:31 AM (17 years, 2 months ago)

OK my tank is a 249 psi size.

Due to the fact that it is PSI i don't think it is liquid. With liquid i doubt they measure the tanks using preasure. I could be wrong.


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"With an abundance of Cyanescens... i would never touch another Cubensis again."

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InvisibleGnuBobo
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Re: Does a empty oxygen cylinder weigh the same full? [Re: pscyanescens]
    #6481541 - 01/21/07 01:32 AM (17 years, 2 months ago)

:bitchsmack:

Does a shot glass of liquor weigh more when it's empty or full?


--------------------
Jerry Garcia. JERRY GARCIA! JERRY GARCIA!!!!

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OfflineNobodyCares
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Re: Does a empty oxygen cylinder weigh the same full? [Re: pscyanescens]
    #6481561 - 01/21/07 01:44 AM (17 years, 2 months ago)

The oxygen and nitrogen above us does "feel really heavy" it's called atmospheric pressure, and it's why our blood would boil in a vacuum. For a tank around 250 PSI, I would guess that it's just pressurized, but not enough to be liquid. Do the tanks feel cold to the touch?


--------------------
The story goes, or the way that I was told
There was a king that always felt too high and then he fell too low
And so he called all the wise men to the hall
And begged them for a gift to end the rises and the falls
But here’s the thing, they came back with a ring
It was simple and was plainly unbefitting of a king
Engraved in black, it had no front or back
But there were words around the band that said
Just know: This Too Shall Pass


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Offlinepscyanescens
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Re: Does a empty oxygen cylinder weigh the same full? [Re: GnuBobo]
    #6481574 - 01/21/07 01:49 AM (17 years, 2 months ago)

Quote:

GnuBobo said:
:bitchsmack:

Does a shot glass of liquor weigh more when it's empty or full?




Who said we were even talking about liquids here?

Not to mention i am really talking about a noticable difference in weight.  And i doubt if i could tell blind folded the difference in weight between a full and empty shot glass.


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"With an abundance of Cyanescens... i would never touch another Cubensis again."

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Offlinepscyanescens
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Re: Does a empty oxygen cylinder weigh the same full? [Re: pscyanescens]
    #6481584 - 01/21/07 01:54 AM (17 years, 2 months ago)

Nope the tanks don't feel cold. Not durring or after using them.

When liquids that boil at low temps turn are converted into gas by boiling, it causes a reduction in temperature. This is similar to how household air conditioning works. For this reason i don't believe my tanks are liquid.

SO........ does your air compressor weigh more full or empty?

Is this the same question?


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"With an abundance of Cyanescens... i would never touch another Cubensis again."

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InvisibleGnuBobo
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Re: Does a empty oxygen cylinder weigh the same full? [Re: pscyanescens]
    #6481675 - 01/21/07 03:36 AM (17 years, 1 month ago)

Dude--the reason a tank is weighted at a given number is because it contains that weight of pressurized gas.


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OfflineNalim
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Re: Does a empty oxygen cylinder weigh the same full? [Re: GnuBobo]
    #6481802 - 01/21/07 07:26 AM (17 years, 1 month ago)

Quote:

Dude--the reason a tank is weighted at a given number is because it contains that weight of pressurized gas.



True!

Quote:

He explains it by saying that determining the atomic weight of oxygen is almost immeasurable. He goes further by saying that if oxygen weighed any considerable amount, then the oxygen above us would be crushing us and making us "feel really heavy" i believe he put it.




Compressed O2 has a molar mass of 32g/mol
At 17atm(249psi) there is 0,695moles of O2/litre
if your tube is 5l then the compressed air weighs 111g


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InvisibleMike_yy
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Re: Does a empty oxygen cylinder weigh the same full? [Re: pscyanescens]
    #6481902 - 01/21/07 08:54 AM (17 years, 1 month ago)

Ive just weighed two identical O2 cylinders (one empty one full),, i only have electronic bathroom scales but one weighed in at 0.05 and the other 0.06...

You can feel a difference when you pick them up anyway,,, kinda obvious.

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Invisiblebadchad
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Re: Does a empty oxygen cylinder weigh the same full? [Re: Mike_yy]
    #6481933 - 01/21/07 09:18 AM (17 years, 1 month ago)

What about a tank of helium?

Does that weigh more or less when full..... ponder ponder.


--------------------
...the whole experience is (and is as) a profound piece of knowledge.  It is an indellible experience; it is forever known.  I have known myself in a way I doubt I would have ever occurred except as it did.

Smith, P.  Bull. Menninger Clinic (1959) 23:20-27; p. 27.

...most subjects find the experience valuable, some find it frightening, and many say that is it uniquely lovely.

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InvisibleCorporal Kielbasa

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Re: Does a empty oxygen cylinder weigh the same full? [Re: pscyanescens]
    #6482016 - 01/21/07 10:03 AM (17 years, 1 month ago)

My Ktanks break my back! More so when they are full. They feel like they gain almost double. What i really want to get is a Dewar tank. But that ways 800 some odd pounds.

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InvisibleCorporal Kielbasa

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Re: Does a empty oxygen cylinder weigh the same full? [Re: pscyanescens]
    #6482024 - 01/21/07 10:07 AM (17 years, 1 month ago)

Small tanks are not liquid. Liquid oxygen has to be at something like -118 Celsius. Anything warmer and it boils and becomes gas. Liquid ox LOX is often held in a Dewar tank.

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OfflinePhychotron
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Re: Does a empty oxygen cylinder weigh the same full? [Re: pscyanescens]
    #6482041 - 01/21/07 10:19 AM (17 years, 1 month ago)

yea, those tanks are heavier when they are full... i used to be into glass blowing. I think the large one's even say the weight on them "full=xx Lb, Empty=xx Lb" but i could be wrong on that. I think i remember there bieng about a 40lb difference, 120-80 full/empty, but again, i could be wrong, it's been awhile.


--------------------
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They tried the truth, It didn't work. Then they wrote the bible. 

Only the foolish fear the inevitable.

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OfflineMadtowntripper
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Re: Does a empty oxygen cylinder weigh the same full? [Re: Corporal Kielbasa]
    #6482130 - 01/21/07 11:11 AM (17 years, 1 month ago)

Quote:

Corporal Kielbasa said:
Small tanks are not liquid. Liquid oxygen has to be at something like -118 Celsius. Anything warmer and it boils and becomes gas. Liquid ox LOX is often held in a Dewar tank.




I was just going to say this.

Liquid oxygen is rocket fuel!


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After one comes, through contact with it's administrators, no longer to cherish greatly the law as a remedy in abuses, then the bottle becomes a sovereign means of direct action.  If you cannot throw it at least you can always drink out of it.  - Ernest Hemingway

If it is life that you feel you are missing I can tell you where to find it.  In the law courts, in business, in government.  There is nothing occurring in the streets. Nothing but a dumbshow composed of the helpless and the impotent.    -Cormac MacCarthy

He who learns must suffer. And even in our sleep pain that cannot forget falls drop by drop upon the heart, and in our own despair, against our will, comes wisdom to us by the awful grace of God.  - Aeschylus

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InvisibleCorporal Kielbasa

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Re: Does a empty oxygen cylinder weigh the same full? [Re: Madtowntripper]
    #6482133 - 01/21/07 11:13 AM (17 years, 1 month ago)

To a lesser degree yes it is. Hydrogen is where it's at though, or as W_S would say helium3 is where it's at.

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Offlinepscyanescens
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Re: Does a empty oxygen cylinder weigh the same full? [Re: Corporal Kielbasa]
    #6483355 - 01/21/07 05:18 PM (17 years, 1 month ago)

Quote:

Nast:
Compressed O2 has a molar mass of 32g/mol
At 17atm(249psi) there is 0,695moles of O2/litre
if your tube is 5l then the compressed air weighs 111g




i know there is a descrepency over how people write numbers.
you mean 0.695 ?

Are you telling me that my tank weighs 22.24 grams more when it is full.

That isn't really that noticable when you concider the tank weighs around 80lbs. or so.


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----------------
"With an abundance of Cyanescens... i would never touch another Cubensis again."

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Offlineentheodome
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Re: Does a empty oxygen cylinder weigh the same full? [Re: badchad]
    #6483692 - 01/21/07 06:42 PM (17 years, 1 month ago)

Quote:

badchad said:
What about a tank of helium?

Does that weigh more or less when full..... ponder ponder.




the tank should weigh the same as empty i suspect.helium is a bit lighter than o2.


--------------------
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InvisibleDieCommie

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Re: Does a empty oxygen cylinder weigh the same full? [Re: entheodome]
    #6483810 - 01/21/07 07:15 PM (17 years, 1 month ago)

Not if the helium is compressed. If the helium is compressed to the point it is heavier than the o2, then naturally the tank would weigh more.

If the tank contained uncompressed helium, then it would weigh less.

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OfflineKonnrade
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Re: Does a empty oxygen cylinder weigh the same full? [Re: entheodome]
    #6483936 - 01/21/07 07:39 PM (17 years, 1 month ago)

Quote:

entheodome said:
Quote:

badchad said:
What about a tank of helium?

Does that weigh more or less when full..... ponder ponder.




the tank should weigh the same as empty i suspect.helium is a bit lighter than o2.




Nope!

Compressed helium is a hell of a lot denser than air. You don't generate lift with something denser than air unless you're on bizarro world. Even if the helium wasn't compressed, the difference woud be marginal... those tanks are heavy as hell and helium is drastically less bouyant than most people realize.


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OfflineApJunkie
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Re: Does a empty oxygen cylinder weigh the same full? [Re: Konnrade]
    #6483959 - 01/21/07 07:43 PM (17 years, 1 month ago)

LOX is totally rocket fuel. Not to a lesser extent at all... It's extremley difficult to manage, but the ISP is amazing. There are certainly better fuels out there, but none that we've been consistently able to tame.

Edit: also, O2 boils at -183* C, if your tank wasn't refridgerated (and I'm not talking about the kind in your kitchen), then it's not liquid oxygen.

Edited by ApJunkie (01/21/07 07:46 PM)

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InvisibleAsante
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Re: Does a empty oxygen cylinder weigh the same full? [Re: Corporal Kielbasa]
    #6484032 - 01/21/07 08:01 PM (17 years, 1 month ago)

Helium 3 is where it's at :thumbup:

Quote:

LOX is totally rocket fuel. Not to a lesser extent at all... It's extremley difficult to manage, but the ISP is amazing. There are certainly better fuels out there, but none that we've been consistently able to tame.




LOX is an oxidizer, it needs a reducer to become a rocket fuel. Its specific impulse derives from the combustion reaction.

LOX + powdered lead has a lousy specific impulse
LOX + methylhydrazine has a staggering specific impulse

It's not the LOX its the interaction of both.


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InvisibleThirdEyeOpening
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Re: Does a empty oxygen cylinder weigh the same full? [Re: ApJunkie]
    #6484064 - 01/21/07 08:08 PM (17 years, 1 month ago)

It seems also that your dealing with small volumes of air too. I have been around Scuba all my life, my parents are both certified instuctors, and my dad used to teach all the time.

When i was into diving, we would deal with high pressure, and fairly high volume tanks. Generally I used a aluminum 80 tank. Which is 80 cubic feet of air at 3000psi. I always used a aluminum tank vs. steel because as you run low on air in the tank, it actually starts to become buoyant. And after filling it, it would become VERY warm, so they are usualy filled while in a large tub filled with water. And more than once have we had to just open a tank up to empty it, and every time the valve forms a thick layer of frost and ice. Simple physics, but still cool to watch.

But yes, the tank WILL be hevier if it has any compressed gas in it, save for some volumes of He and H, due to there natural weight. it may only be a few ounces or so depending on the pressure and volume of the cylinder.

And at the facilitiy my dad worked at, the owner has about 150 or so of the 8 foot tall tanks. They are all linked together in a high pressure bank (5000psi) and a low pressure bank (3000psi). And let me tell you, moving one of those fuckers around when its full of a heavy gas like Argon (used for a insulation gas when dry-suit diving) vs. helum (for heliox, or trimix), or even an empty tank, give me an empty one any day.

Oh and i doubt i have seen anyone jump higher or have the shit scared out of them more than when one of my buddies was over and a high pressure bank tank blew a burst disk. It sounds like a gernade, and then the most high pitch squeil you will ever hear. Untill the tank is empty and isolated, but it still bleeds out for ~10-15 min.


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Offlinepscyanescens
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Re: Does a empty oxygen cylinder weigh the same full? [Re: ThirdEyeOpening]
    #6484187 - 01/21/07 08:29 PM (17 years, 1 month ago)

ThirdEyeOpening : A few ounces? What about 24.24 grams. or 111 grams? What about the scientific evidence posted in the thread earlier?

We are taling about pure oxygen. The kind that is not OK to breath.

The air we breath is Oxygen by only a small percent. I forget what it is but its less then 20% and the majority is Nitrogen.


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----------------
"With an abundance of Cyanescens... i would never touch another Cubensis again."

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Re: Does a empty oxygen cylinder weigh the same full? [Re: pscyanescens]
    #6484284 - 01/21/07 08:49 PM (17 years, 1 month ago)

You must make a distinction between mass and weight here.

By adding a gas to a cylinder you are necessarily increasing its mass.

However, at low pressures, H2 and He have a lower density than air (~79% N2, 21% O2) and as such, an effectively lower weight. COMPRESSED gases, of course, are at a higher pressure than atmospheric, and will be more dense than usual, resulting in MORE weight.

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InvisibleKid_Orgo
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Re: Does a empty oxygen cylinder weigh the same full? [Re: pscyanescens]
    #6484318 - 01/21/07 08:55 PM (17 years, 1 month ago)

I can't believe this thread is still going.


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Offlinepscyanescens
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Re: Does a empty oxygen cylinder weigh the same full? [Re: Chesh]
    #6484321 - 01/21/07 08:55 PM (17 years, 1 month ago)

Quote:

Chesh said:
You must make a distinction between mass and weight here.

By adding a gas to a cylinder you are necessarily increasing its mass.

However, at low pressures, H2 and He have a lower density than air (~79% N2, 21% O2) and as such, an effectively lower weight. COMPRESSED gases, of course, are at a higher pressure than atmospheric, and will be more dense than usual, resulting in MORE weight.




My question once again. How much weight. I know it will increase somehow. You are adding sometihing to it. Is it noticable? 24g or 111g is not that noticable, given the tanks weight.


--------------------
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Offlinepscyanescens
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Re: Does a empty oxygen cylinder weigh the same full? [Re: pscyanescens]
    #6484327 - 01/21/07 08:57 PM (17 years, 1 month ago)

Kid_orgo: Why nobody has answered the questions i just asked above. I hope this thread doesn't die unanswered.


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"With an abundance of Cyanescens... i would never touch another Cubensis again."

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OfflineNalim
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Re: Does a empty oxygen cylinder weigh the same full? [Re: pscyanescens]
    #6484399 - 01/22/07 01:11 AM (17 years, 1 month ago)

How many liters does your tank hold? how high pressure?

If the pressure is 249ponds per square inch and the volume is 1 liter then your tube weighs about 22.2g more when its full.

Larger tubes can have much higher pressure and have much larger volume and are therefore much heavier.

the formula you use is this:

mass=n*M=((P*V)/(R*T))*M

P=pressure
V=volume
R=0.08206
T=temperature in degrees Kelvin
M=molar mass
n=number of molecules(in moles)


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Nalim said: "Quoting yourself is retarded."

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OfflineChesh


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Re: Does a empty oxygen cylinder weigh the same full? [Re: Nalim]
    #6484431 - 01/22/07 01:33 AM (17 years, 1 month ago)

Yeah, pscyanescens, i'm sorry for not answering your question directly. As Nast said, the amount of gas, and thus the change in weight depends on the volume, as well as the pressure and identity of the gas, and i didn't see a specific volume listed.

Nast: the molar gas constant you listed is for Liters and Atmospheres. To change it into Liters and PSI, multiply by 14.696 PSI(in 1 Atm) =
1.206 = R ...i think....

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OfflineNalim
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Re: Does a empty oxygen cylinder weigh the same full? [Re: Chesh]
    #6484564 - 01/22/07 03:23 AM (17 years, 1 month ago)

1 psi = 6,8046 · 10^-2 atm = 0,06805
R is indeed a konstant that depends on which units you use..
the units I used to calculate the stuff above is Liters, Atmospheres and degrees Kelvin...

If you are going to use other units then you need to look up the universal gas constant for those units(or calculate it, I just dont feel like it right now, it just might be what you said Chesh)...


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Offlinepscyanescens
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Re: Does a empty oxygen cylinder weigh the same full? [Re: Nalim]
    #6484592 - 01/22/07 03:55 AM (17 years, 1 month ago)

OK i am very very sorry

My stupid friend who i asked to check the tank size, came back and said it was 249 PSI.

I just looked at it and it says 249 CUFT
I am going to take a stab in the dark and call this Cubic Feet.

Can anyone give me a conversion to do the math with this?
Here is a picture.


I was thinking 5 liters???? This is the second to largest tank they will give us before we get bumped up to a liquid oxygen tank.

And as far as liquid oxygen goes for being rocket fuel, Oxygen is an accelerant, i could be wrong but i know it is not actually flammable. It just gives more power to the flame. Try holding a lighter up to torch with the oxy running. It wont light, it will just make the flame from the lighter hotter. This is the reason i need to mix it with propane before i have a workable flame.


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OfflineNalim
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Re: Does a empty oxygen cylinder weigh the same full? [Re: pscyanescens]
    #6484648 - 01/22/07 04:38 AM (17 years, 1 month ago)

1 cubic foot is equivalent to: 28.316846592 liters (from wikipedia)
I still need to know the pressure in the tube to be able to calculate the weight of the O2.

Quote:

And as far as liquid oxygen goes for being rocket fuel, Oxygen is an accelerant, i could be wrong but i know it is not actually flammable. It just gives more power to the flame. Try holding a lighter up to torch with the oxy running. It wont light, it will just make the flame from the lighter hotter. This is the reason i need to mix it with propane before i have a workable flame.




this is what rocket-fuel is and what happens when it burns:
O2 and H2 is rocket-fuel, the reaction that takes place is;
½O2 + H2=>H2O+energy


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OfflineColbadol
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Re: Does a empty oxygen cylinder weigh the same full? [Re: Nalim]
    #6484655 - 01/22/07 04:46 AM (17 years, 1 month ago)

and the temperature.

if you know your volume, temp, molecular weight, and pressure, the mass is just:

m = p*v*M/(R*T)

remember to always use absolute pressure (not gage), and to keep your units right. 1 atm = 14.7psi = 1.013x10^5 pascals. Use Pascals. R = 8314 J/kgmol.K. M = molecular weight (in kg/kgmol.K) And use kelvin for temp (deg celsius + 273).


edit: sry, i didnt really read the posts. this was already answered.


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Edited by Colbadol (01/22/07 04:57 AM)

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Offlinepscyanescens
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Re: Does a empty oxygen cylinder weigh the same full? [Re: Colbadol]
    #6484680 - 01/22/07 05:05 AM (17 years, 1 month ago)

Well i don't know how to determine the PSI. However on my regulator, i can turn it ll the way up to 300 PSI. It will more then likely go further, however i am reluctant to turn it up that high. The regulator should be able to take it, but i am overly cautious with allot of things.


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OfflineColbadol
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Re: Does a empty oxygen cylinder weigh the same full? [Re: pscyanescens]
    #6484722 - 01/22/07 05:44 AM (17 years, 1 month ago)

i looked around online at oxygen tanks of similar size, and those were all around 2200psig max.
2200 + 14.7 = 2214.7psia = 15.26MPa
250ft^3 = 7079.2L = 7.08m^3
M = 32
T = 21 + 273 = 294K


m = 15.2e6 *7.08*32/(8314*294)
m = 1408.86kg

idk, that seems very high. i prob made a mistake, lol sooo early in the morning

edit: oh yeah. when the tank is empty:

m = 1.013e5*7.08*32/(8314*294)
m = 9.38kg

difference of about 1400kg?
yeah. i think i made a mistake.


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Edited by Colbadol (01/22/07 05:52 AM)

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Offlinepscyanescens
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Re: Does a empty oxygen cylinder weigh the same full? [Re: Colbadol]
    #6484736 - 01/22/07 05:55 AM (17 years, 1 month ago)

LOL well we are getting closer.:D


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Re: Does a empty oxygen cylinder weigh the same full? [Re: pscyanescens]
    #6484737 - 01/22/07 05:59 AM (17 years, 1 month ago)

Quote:

Does a empty oxygen cylinder weigh the same full?




NO
:snowman:


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Re: Does a empty oxygen cylinder weigh the same full? [Re: pscyanescens]
    #6484745 - 01/22/07 06:06 AM (17 years, 1 month ago)

Put empty tank on scale. Record weight.


Put full tank on scale. Record weight.


Compare the numbers.

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Re: Does a empty oxygen cylinder weigh the same full? [Re: pscyanescens]
    #6484754 - 01/22/07 06:13 AM (17 years, 1 month ago)

Quote:

pscyanescens said:







yeah yeah what ever, I'm sure the real question here is where the hell did you get that giant fender pick?

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Re: Does a empty oxygen cylinder weigh the same full? [Re: Stein]
    #6484762 - 01/22/07 06:20 AM (17 years, 1 month ago)

Quote:

Stein said:
Quote:

pscyanescens said:







yeah yeah what ever, I'm sure the real question here is where the hell did you get that giant fender pick?





?????????????
Well?


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Offlinepscyanescens
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Re: Does a empty oxygen cylinder weigh the same full? [Re: Psilocybeingzz]
    #6484842 - 01/22/07 07:20 AM (17 years, 1 month ago)

LOL. I got it from Big Foot.

No.... actually it was brought here by my roommate. He is a strange one, but he did teach me to blow glass. I have no idea where he got it.

Booooom: I have been meaing to do this. But i don't have a scale. I would have to go to my parents house and take one. Never the less i will do this. I was just looking for maybe a little math and equations to give me some answers. I know it will weigh more, but is it going to be noticeable?

I would love to rub some info in the owner of the oxy shops face. I think that facts and mathematical equations would make him listen more. Rather me just saying , i weighed it and the difference is "X"

It still would be good to do ti myslef, but some facts are always nice to throw around.


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Offlinepscyanescens
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Re: Does a empty oxygen cylinder weigh the same full? [Re: Boom]
    #6484927 - 01/22/07 08:12 AM (17 years, 1 month ago)

Quote:

Booooom said:
Put empty tank on scale. Record weight.


Put full tank on scale. Record weight.


Compare the numbers.




Do all the oxy tanks that are 249CUFT weigh the same? I think i will weigh a full one first, and then use the oxygen inside it, then weigh the same exact tank empty. This seems a little more practical.


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InvisibleThirdEyeOpening
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Re: Does a empty oxygen cylinder weigh the same full? [Re: pscyanescens]
    #6484986 - 01/22/07 08:35 AM (17 years, 1 month ago)

I dont know why but i couldent log on to the shoomery last night to finish but this is what i came up with.

Well, im usually lazy and that was really just a guesstamate. But for the math, using the molecular weight and doubling it since its O2, 32g/mol, and 1 mol = 22.4 liters, and your tank is rated to 249 cubic foot at 2200 psi.


1 cubic foot of gas at STP = 28.3 liters

22.4 liters = 1 mol o2 = 32g

32/22.4 = 1.4285

1.4285 x 28.3 = 40.43g / cubic foot



Pressure doesnt really matter, because the tanks are rated so that when the tank is filled to X pressure they will hold Y volume of gas.

so for example, a 249 cubic foot tank, at 2200 psi, has 249 cubic feet of gas

but if its only at 1500psi it will have 167.7 cubic feet of gas.


249/2200 = .08

.112 x 1500 = 167.7 cubic feet.



Beware my math, its been a LONG time since i have done gas eqations.

Edited since the cubic feet and pressure was listed.


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Edited by ThirdEyeOpening (01/22/07 08:52 AM)

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OfflineApJunkie
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Re: Does a empty oxygen cylinder weigh the same full? [Re: Asante]
    #6485076 - 01/22/07 09:13 AM (17 years, 1 month ago)

Quote:

Wiccan_Seeker said:

LOX is an oxidizer, it needs a reducer to become a rocket fuel. Its specific impulse derives from the combustion reaction.

LOX + powdered lead has a lousy specific impulse
LOX + methylhydrazine has a staggering specific impulse

It's not the LOX its the interaction of both.




Yeah man I know :laugh:

I didn't feel the need to go too far into it since the question was about weight rather than applied properties, but you're right, LOX is an oxidizer. However, the high ISP when used with the correct reducer is not worth it IMO... the absurd temps and inherent dangers with using it don't add up enough. :shrug:

My fuel of choice: NH4ClO4 + Al + HTPB binder.... When leaving the effects catalysts out (which doesn't always happen... people like their colored flames :tongue:) you can get specific impulse in the range of 260 seconds :thumbup:

I've heard a little bit about Helium 3, but if I understand correctly that's more for interplanetary travel, not exactly my field. :smile:

Edited by ApJunkie (05/04/07 12:33 AM)

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Offlinepscyanescens
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Re: Does a empty oxygen cylinder weigh the same full? [Re: ApJunkie]
    #6486699 - 01/22/07 05:22 PM (17 years, 1 month ago)

What do you do for a living? Do you work with NASA?


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