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Metalworking (rec.crafts.metalworking) Discuss various aspects of working with metal, such as machining, welding, metal joining, screwing, casting, hardening/tempering, blacksmithing/forging, spinning and hammer work, sheet metal work. |
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#1
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Markings on CO2 cylinder? Is it a rental?
I have a CO2 fire extinguisher which i bought at a garage sale a few
years ago very cheaply. It is out of testing dates and will need to be retested, I have just had it sitting in my shed and i am about to take it in to get it re-tested so i can use it for MIG welding. Is there likely to be any legal issues with it, could it be an ex- rental or something? If so what markings do i need to look for to be able to tell this as i don't know any of its history? Any help or information would be much appreciated, Joseph |
#3
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Markings on CO2 cylinder? Is it a rental?
wrote: I have a CO2 fire extinguisher which i bought at a garage sale a few years ago very cheaply. It is out of testing dates and will need to be retested, I have just had it sitting in my shed and i am about to take it in to get it re-tested so i can use it for MIG welding. Not a good idea as fire bottles are not all rated for the same pressure levels as are welding bottles. Working pressure for CO2 extinguishers are 2/3's or lower than those normally used for bulk CO2. The highest rated portable fire bottle that I could find was only rated for 2000psi working pressure. |
#4
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Markings on CO2 cylinder? Is it a rental?
wrote:
wrote: I have a CO2 fire extinguisher which i bought at a garage sale a few years ago very cheaply. It is out of testing dates and will need to be retested, I have just had it sitting in my shed and i am about to take it in to get it re-tested so i can use it for MIG welding. Not a good idea as fire bottles are not all rated for the same pressure levels as are welding bottles. Working pressure for CO2 extinguishers are 2/3's or lower than those normally used for bulk CO2. The highest rated portable fire bottle that I could find was only rated for 2000psi working pressure. http://scifun.chem.wisc.edu/chemweek/CO2/CO2.html At 20C it looks like the tank will be at 14.7 * 30 ATM or 441 PSI. Seems like 2000psi would work. Wes |
#5
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Markings on CO2 cylinder? Is it a rental?
Wes wrote: http://scifun.chem.wisc.edu/chemweek/CO2/CO2.html At 20C it looks like the tank will be at 14.7 * 30 ATM or 441 PSI. Seems like 2000psi would work. The problem Wes, is how are you going to flag the cylinder to the gas monkeys that charge the bottle that it won't take the normal fill pressure? All they look at is the color and the valve before charging it. Do you really want to put a bottle that is only capable of 2000psi onto a charging line that fills bottles to 3000 or 3500 psi? I don't know about you, but I darned sure don't want to be within a mile of that place when it happens. I've been around a bottle facility that went up in flames before. The fire department found O2 and CO2 bottles as far as 7 miles down range. We just had a small facility go up in flames here in the DFW area just a couple of weeks ago. DFD found ruptured bottles as far as a mile away from that one and it was tiny compared to the one that I saw as a kid in Houston. I work around high pressure gas systems every day and minor mistakes can kill you and anyone around you in an instant. We had someone put down the incorrect test pressure when an accumulator was changed out. The resulting explosion didn't hurt anyone because it was contained, but it did cost well into 6 figures to repair the damage done. This is one place where shortcuts and trying to cheap- charley it, will bit you. |
#6
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Markings on CO2 cylinder? Is it a rental?
On Sat, 01 Sep 2007 23:58:03 -0700, wrote:
Wes wrote: http://scifun.chem.wisc.edu/chemweek/CO2/CO2.html At 20C it looks like the tank will be at 14.7 * 30 ATM or 441 PSI. Seems like 2000psi would work. The problem Wes, is how are you going to flag the cylinder to the gas monkeys that charge the bottle that it won't take the normal fill pressure? All they look at is the color and the valve before charging it. Do you really want to put a bottle that is only capable of 2000psi onto a charging line that fills bottles to 3000 or 3500 psi? Umm. Why would you fill any CO2 bottle to that pressure? it won't get any more gas in and you'd have to partially empty it to make it safe for storage after filling. Mark Rand RTFM |
#7
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Markings on CO2 cylinder? Is it a rental?
Keywords:
In article om, wrote: Wes wrote: http://scifun.chem.wisc.edu/chemweek/CO2/CO2.html At 20C it looks like the tank will be at 14.7 * 30 ATM or 441 PSI. Seems like 2000psi would work. The problem Wes, is how are you going to flag the cylinder to the gas monkeys that charge the bottle that it won't take the normal fill pressure? All they look at is the color and the valve before charging it. Do you really want to put a bottle that is only capable of 2000psi onto a charging line that fills bottles to 3000 or 3500 psi? I don't know about you, but I darned sure don't want to be within a mile of that place when it happens. I've been around a bottle facility that went up in flames before. The fire department found O2 and CO2 bottles as far as 7 miles down range. We just had a small facility go up in flames here in the DFW area just a couple of weeks ago. DFD found ruptured bottles as far as a mile away from that one and it was tiny compared to the one that I saw as a kid in Houston. I work around high pressure gas systems every day and minor mistakes can kill you and anyone around you in an instant. We had someone put down the incorrect test pressure when an accumulator was changed out. The resulting explosion didn't hurt anyone because it was contained, but it did cost well into 6 figures to repair the damage done. This is one place where shortcuts and trying to cheap- charley it, will bit you. I don't think you understand the physics of CO2. It turns to a liquid at moderate pressures (i.e. well under 1000 PSI, depending on the temperature). You can try to push as much C02 into the bottle as you want, but you can't get the pressure higher than that without getting it really hot. It just turns to liquid and fills the tank up. It's not like nitrogen and a lot of other gasses that don't liquify until you get to really high pressures. You can fill a cylinder completely with liquid, and it STILL won't be at a dangerous pressure. The only risk would be if someone filled it completely with liquid and then sealed it, because then it's imcompressible and a temperature rise could cause a problem. Anyone who is filling a CO2 cyclinder commercially will understand this, and there shouldn't be an issue. The downside of using a fire extinguisher tank is that it isn't designed to be banged around like a commercial gas cylinder. They are supposed to hang on the wall & be used in emergencies. As long as you treat them carefully, there shouldn't be a problem if it's been hydrotested in recent memory. Doug White |
#8
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Markings on CO2 cylinder? Is it a rental?
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#9
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Markings on CO2 cylinder? Is it a rental?
wrote:
Wes wrote: http://scifun.chem.wisc.edu/chemweek/CO2/CO2.html At 20C it looks like the tank will be at 14.7 * 30 ATM or 441 PSI. Seems like 2000psi would work. The problem Wes, is how are you going to flag the cylinder to the gas monkeys that charge the bottle that it won't take the normal fill pressure? All they look at is the color and the valve before charging it. Do you really want to put a bottle that is only capable of 2000psi onto a charging line that fills bottles to 3000 or 3500 psi? I don't know about you, but I darned sure don't want to be within a mile of that place when it happens. I've been around a bottle facility that went up in flames before. The fire department found O2 and CO2 bottles as far as 7 miles down range. We just had a small facility go up in flames here in the DFW area just a couple of weeks ago. DFD found ruptured bottles as far as a mile away from that one and it was tiny compared to the one that I saw as a kid in Houston. I work around high pressure gas systems every day and minor mistakes can kill you and anyone around you in an instant. We had someone put down the incorrect test pressure when an accumulator was changed out. The resulting explosion didn't hurt anyone because it was contained, but it did cost well into 6 figures to repair the damage done. This is one place where shortcuts and trying to cheap- charley it, will bit you. CO2 bottles are filled by weight, not pressure. Similar to BBQ propane, the CO2 is a liguid under a layer of gas in the bottle. No worries. And it's not like acetylene, where filling the bottle too fast or to too high a pressure will make things go ugly. Let the guys at the depot decide if the bottle is a disposable or if it's refillable. If it is not of the disposable variety, they will be quite OK with hydro and fill. Cheers Trevor Jones |
#10
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Markings on CO2 cylinder? Is it a rental?
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#11
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Markings on CO2 cylinder? Is it a rental?
Doug: I do remember most of the physics of pure CO2, but in this case
I'll plead brain fart partially due to way too many days with nearly no sleep over the last couple of weeks. It's also been nearly 15 years since I worked with CO2 by itself. Normally I deal with N2 and O2 and mixtures of various gases at pressures well above 2000 psi as well as LN2 and LOX. What I remembered, and missed was the absolute pressures on the vapor pressure curve given the bottle fill percentage vs. ambient temp. What I was remembering correctly is that the bottle pressure will rise approximately 500 psi for a jump in bottle temp between 80F and 90F, when the bottle is over 60% full and less than about 90% full. I simply displaced the curve about 50% upward. BTW: There are now some commercial processes that are using CO2 in liquid form at pressures in the 1500-2000psi range. |
#12
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Markings on CO2 cylinder? Is it a rental?
I think the intension - I hope - is to use it as fire prevention.
Normally they are to small for MIG except for tiny pony and portables. The largest I have seen was mounted on two 4' tall metal wheels. But the largest tank CARDOX was outside a paint house at a GM plant. Fire suppress the entire building in seconds. Martin Martin H. Eastburn @ home at Lions' Lair with our computer lionslair at consolidated dot net TSRA, Life; NRA LOH & Endowment Member, Golden Eagle, Patriot's Medal. NRA Second Amendment Task Force Charter Founder IHMSA and NRA Metallic Silhouette maker & member. http://lufkinced.com/ wrote: I have a CO2 fire extinguisher which i bought at a garage sale a few years ago very cheaply. It is out of testing dates and will need to be retested, I have just had it sitting in my shed and i am about to take it in to get it re-tested so i can use it for MIG welding. Is there likely to be any legal issues with it, could it be an ex- rental or something? If so what markings do i need to look for to be able to tell this as i don't know any of its history? Any help or information would be much appreciated, Joseph ----== Posted via Newsfeeds.Com - Unlimited-Unrestricted-Secure Usenet News==---- http://www.newsfeeds.com The #1 Newsgroup Service in the World! 120,000+ Newsgroups ----= East and West-Coast Server Farms - Total Privacy via Encryption =---- |
#13
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Markings on CO2 cylinder? Is it a rental?
wrote in message oups.com... I have a CO2 fire extinguisher which i bought at a garage sale a few years ago very cheaply. It is out of testing dates and will need to be retested, I have just had it sitting in my shed and i am about to take it in to get it re-tested so i can use it for MIG welding. Is there likely to be any legal issues with it, could it be an ex- rental or something? If so what markings do i need to look for to be able to tell this as i don't know any of its history? Any help or information would be much appreciated, Joseph Lots of good advice from others but I did not notice anyone letting you know that fire extinguisher bottles have a dip tube to draw liquid from the bottom of the bottle when being discharged. For welding you will want to draw gas from the top. This should not be a problem if the valve is replaced, as the dip tube is connected to the valve. Just for your information. Don Young |
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