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Zippymbr
05-19-2008, 05:51 PM
Well I found some nice bottles on Craigslist. I was wondering of the 100 cubic foot Acetylene bottle was full at 110 psi? The Oxygen bottle was at 1600 psi and is a 140 cubic foot. The guy had several sets and will bring me another if these are not full.

hankj
05-19-2008, 07:15 PM
Acetylene tanks are not high pressure cylinders. Depending on the ambient temperature and the actual fill capacity of the tank (a 145 ft Acetylene tank holds 126 ft of actual CH) the pressures can vary widely.

I'd say a 100 ft acetylene tank could be close to full at 100 psi in a warm environment. My 145 uaually reads ~275 psi or so when I swap it, but the little 40 on my mini outfit is usually ~ 125.

Hank

dsw
05-20-2008, 11:56 AM
All said, temps will quickly change the pressure in a tank. Leave a tank outside all night in 15F and it will read significantly lower than if it is kept inside at 75F. no change in volume just pressure.

The acet. I'm not sure about, but it seems a bit light, say maybe 3/4 full? I seldom use my acet. tank so can't remember what it reads full. The O2 is definitely down. A full bottle should read between 2200psi and 2400psi depending on temps. I doubt it would go to 1600psi from full even if stored below 0. I handle O2 every day so i know spot on what that should be.

The size of the bottle will not matter to pressure on O2. A full 282cf bottle of O2 would read 2200psi and so would a 60cf bottle. How much gas is in the bottle is in proportion to the size and pressure.

Example 100 cf bottle. Full 100 cf 2200psi. 3/4 full 75cf or (3/4 of 2200psi) 1650 psi. 1/2 full 50 cf (50% of 2200psi) 1100 psi. 1/4 full 25 cf (1/4 of 2200 ) or 550 psi.

If it was a 282cf bottle the psi will be the same but the volume will be different. 282cf, 211cf, 140cf, 70cf

This generally works with any gas O2, Helium, Argon, C25, nitrogen. It will not work for CO2 as this is generally a liquid and you just pull the gas off the top.


Hope this helps and makes sense.

weldgault
05-20-2008, 01:56 PM
Acetylene tanks are not high pressure cylinders. Depending on the ambient temperature and the actual fill capacity of the tank (a 145 ft Acetylene tank holds 126 ft of actual CH) the pressures can vary widely.

I'd say a 100 ft acetylene tank could be close to full at 100 psi in a warm environment. My 145 uaually reads ~275 psi or so when I swap it, but the little 40 on my mini outfit is usually ~ 125.

Hank




Acetylene is filled to 250 psi @70 Degrees. calcium carbide, when mixed with water gives off a gas (acetylene), that is 14.7 CU FT per Lb. The only way to exactly know how full the cylinder is weigh it. There is a TW (tare Weight) stamped on the cylinder, so substract the tare weight from the full weight and multiply by 14.7 and you will know how many CUFT is in the cylinder. Example: TW on the cylinder reads 100# and the cylinder weighs 110#, you have 147 cuft in the cylinder. John

Zippymbr
05-20-2008, 04:37 PM
Acetylene is filled to 250 psi @70 Degrees. Acetone, when mixed with water gives off a gas (acetylene), that is 14.7 CU FT per Lb. The only way to exactly know how full the cylinder is weigh it. There is a TW (tare Weight) stamped on the cylinder, so substract the tare weight from the full weight and multiply by 14.7 and you will know how many CUFT is in the cylinder. Example: TW on the cylinder reads 100# and the cylinder weighs 110#, you have 147 cuft in the cylinder. John

Ok, that makes sense to me. Thanks

cpurvis
05-20-2008, 07:53 PM
Acetylene is filled to 250 psi @70 Degrees. Acetone, when mixed with water gives off a gas (acetylene), that is 14.7 CU FT per Lb. The only way to exactly know how full the cylinder is weigh it. There is a TW (tare Weight) stamped on the cylinder, so substract the tare weight from the full weight and multiply by 14.7 and you will know how many CUFT is in the cylinder. Example: TW on the cylinder reads 100# and the cylinder weighs 110#, you have 147 cuft in the cylinder. John

I agree, weighing is the only accurate way.

Is it acetone/water or calcium carbide/water which generates acetylene gas? I was thinking it is calcium carbide. That's how the old miner's lamps worked, I believe.

weldgault
05-20-2008, 08:06 PM
I agree, weighing is the only accurate way.

Is it acetone/water or calcium carbide/water which generates acetylene gas? I was thinking it is calcium carbide. That's how the old miner's lamps worked, I believe.


You are correct, typing and brain not in cink. Thanks for catching that. John

hankj
05-20-2008, 08:17 PM
.....A full bottle should read between 2200psi and 2400psi......

Only if the cylinder is rated for that pressure. There are a lot of older 3AA's around still rated at 1800.

Hank

weldgault
05-20-2008, 09:56 PM
Only if the cylinder is rated for that pressure. There are a lot of older 3AA's around still rated at 1800.

Hank



There are 1800, 2015, 2265 and 2400's. These can be filled 10% over their rating if the date has a star by the date of testing. It has met the 10% over fill testing. Making a 2015, 2216 PSI when full. John

dsw
05-20-2008, 10:44 PM
You all are correct about the different tanks. I never see any of the 1800's or 2015's from any of my O2 suppliers, so I didn't even think of them. I have used a bunch of those older ones to build air banks for customers. Most pick up the bottles from the hydro shop as they are phased out of the general rotation.

weldgault
05-21-2008, 12:07 AM
You all are correct about the different tanks. I never see any of the 1800's or 2015's from any of my O2 suppliers, so I didn't even think of them. I have used a bunch of those older ones to build air banks for customers. Most pick up the bottles from the hydro shop as they are phased out of the general rotation.



When a 2015 cylinder doesn't pass the high pressure test, most are turned into 50# CO2 cylinders. John

dsw
05-21-2008, 01:13 AM
There's a tid bit of info I did not know. May also explain why thehydro shop I use tends to collect a bunch of older tanks. The do hydro's for ships. The ship can't leave port unless all their tanks are up to spec for coast guard inspections. They get tractor trailers of tanks some times for hydro. I asked what all the bottles are for and was told fire suppression. Converting the 2015's to Co2 would make sense then.

BTW I was talking to the guy who does most of the hydro's there. He gets calls in the middle of the night to come in open up and hydro tanks. One customer drives the tanks up from Port of Baltimore and then waits while he hydro's the tanks and then takes them back. Everything stops for this customer if they show up during the day until their job is finished. They pay BIG money for this service. I talked to one driver from Balt. while I waited for his tanks to be finished so I could get my paperwork. The cost of docking fees is so high that its cheap for the shipping company to have this special service done so they can get out of port as fast as possible.

weldgault
06-02-2008, 01:26 PM
There's a tid bit of info I did not know. May also explain why thehydro shop I use tends to collect a bunch of older tanks. The do hydro's for ships. The ship can't leave port unless all their tanks are up to spec for coast guard inspections. They get tractor trailers of tanks some times for hydro. I asked what all the bottles are for and was told fire suppression. Converting the 2015's to Co2 would make sense then.

BTW I was talking to the guy who does most of the hydro's there. He gets calls in the middle of the night to come in open up and hydro tanks. One customer drives the tanks up from Port of Baltimore and then waits while he hydro's the tanks and then takes them back. Everything stops for this customer if they show up during the day until their job is finished. They pay BIG money for this service. I talked to one driver from Balt. while I waited for his tanks to be finished so I could get my paperwork. The cost of docking fees is so high that its cheap for the shipping company to have this special service done so they can get out of port as fast as possible.



Next time you see a large CO2 cylinder, check and see if it a 2015 cylinder. They also convert them to soda fountain CO@ with A dip tube on the valve, to get liquid and not gas. John