Initial fill of new Propane tank fact or fiction on purge needed

Maybe it was anything -- aerosol can(s), can of peaches, case of pepsi, juggles the dog. That's the falacy of most cause/effect assumptions--no data.

The opd isn't required on all tanks. Maybe your tank is one of the exceptions. Is it horizontal, permanent mount, or what?

Or one of the tires. More likely than the propane tank.

Your take is wrong. Due to environmental issues, the tank is NOT vented to the atmosphere when filling by weight. The valve is connected to the filler hose, the valve opened, and the pump started. There is NOTHING in the tank but propane - either in liquid or vapour state. The tank is filled to 80% max capacity with liquid. The other

20% is pure pressurized propane. Now, if the tank is NOT purged, it starts out full of air at atmospheric pressure. It is compressed to 5 atmospheres pressure if below the boiling point of propane, and comprises a flammable mixture inside the tank at some temperature between there and normal ambient. Not likely a big safety issue - but there IS a point where an explosive mixture exists inside a non purged tank.

When the tank is "used up" it does not have air in it if it started out purged - and would have VERY little even if not purged - assuming the valve did not freeze etc. So refilling the tank does NOT require venting. A "brown valve" on a vehicle tank also eliminates the requirement to vent the tank when filling. As soon as the liquid level reaches the bottom of the tube (80% mark) the fuel flow is shut off. Venting of propane tanks at fillup is currently illegal in many areas

- as it should be - for both safety and environmental reasons.

False.

True, eventually.

kaboom! I thought that maybe the

Hard to believe but I'm pretty sure the tank in that motor home didn't much care what this group decides.

Ok, so I exaggerated a bit since the total pressure is equal to the total of the partial pressures. If you took all the air in the tank at 1 atmosphere and compressed it into the space above the liquid nitrogen (compressed bout 5 times?) the psi would be pretty low and much lower than the propane gas. Since gas volume and pressure are inversely related and one atmosphere =14.7 psi, the pressure would be 5 x 14.7 or 73.9 psi. So just add that to the pressure of the propane which someone suggest was at least 200 psi. I don't think that has any significance for safety, unless they make awfully weak bottles.

Ive never seen anyone fill a tank with a scale before. I get mine filled and they simply pump in 4.5 gal with the bleeder open and call it good. Every place I frequent in So.Cal. does it this way. The older none OPD tanks would take a full 5 gallons done this way. I ran out of propane earlier this week in my RV as I forgot that I have a half gallon less now than before.

Gunner

" ..The world has gone crazy. Guess I'm showing my age... I think it dates from when we started looking at virtues as funny. It's embarrassing to speak of honor, integrity, bravery, patriotism, 'doing the right thing', charity, fairness. You have Seinfeld making cowardice an acceptable choice; our politicians changing positions of honor with every poll; we laugh at servicemen and patriotic fervor; we accept corruption in our police and bias in our judges; we kill our children, and wonder why they have no respect for Life. We deny children their childhood and innocence- and then we denigrate being a Man, as opposed to a 'person'. We *assume* that anyone with a weapon will use it against his fellowman- if only he has the chance. Nah; in our agitation to keep the State out of the church business, we've destroyed our value system and replaced it with *nothing*. Turns my stomach- " Chas , rec.knives

Not horizontal. Not permanent mount. Just a garden variety 100lb LP tank. Vertical, about 4 or 5 feet tall, a 12 to 18 inches or so in diameter, weighs about 40 pounds empty. (hard to judge, and I didn't see a tare weight stamped on it)

The tanks are in a storage unit, now that they are cleaned and full of compressed air. The valves are still in the garage.... crap. No they ain't. I must have tossed them in the trash.

Dave

I've gotten Propane and Butane and that hide the facts LPG type of stuff for 40+ years.

I used to have to get mine at a wholesale dealer - drive up the the pump stand - where the semi-trailer tankers get a drink themselves.

There they used a scale. Read the weight off the side and went from there. They hated the tiny bottles but heck - propane was their lives. In the winter, when cold - they would just fill up to the overflow.

So I think it was a matter of safety. A hot day might outgass the tank on the way home.

Around here - always by the overflow - but then it is at a gas station...

Propane by nature maintains a somewhat constant pressure within when not frozen. The gas expands and when the pressure builds up - it turns back into liquid.

My brother-in-law used to work for Neptune and ? Gas Equipment - the folks that made the gas meters for propane.

OPD not required YET on 100lb cyls , up here anyway. 20 and under are definitely mandated. Not sure on the 50s.

Those are 15 gallon tanks - I hate the tall unstable size. I'd rather have a shorter fatter one myself.

I plan on measuring my hoses before I get back to work - just in case I have to have new ones built - suspect I do.

Martin

No, more like 26 psi (0 deg F), 122 psi (70 deg F), or 190 psi (100 deg F).

I suppose now someone will ask, "hey, can I use my propane tank to run my air tools without a compressor?"

Sure -- until the first spark. :-)

A die grinder with front exhaust would be an interesting experience -- outdoors. :-)

Something else -- indoors -- might be the last thing you do.

Or -- a die grinder with rear exhaust would really call for Nomex work clothes. :-)

Enjoy, DoN.

I said "fogged", not liquid. Low-temperature vapor, not liquid drops. I've done enough gravity filling to know the difference. They fill by weight, kind of hard to overfill if the scale is set correctly. Might be improperly done in your locale or by your standards, though. It DID get rid of the air or gas in there, the actual object of the exercise.

Well, it's between 6-10% humidity here in the summer, the air or gas is venting OUT, so just how is water vapor supposed to be going back in???? It was hauled over to the rental outfit for filling that day anyway. It was just curious to me that there was that much compressed gas in there already.

One of the other posters figured partial pressure on the basis of the initial air or inert fill gas being at atmospheric pressure. It wasn't at atmospheric pressure, for as long as it bled it had to be at higher pressure than that. Can't be all that much higher, though, the DOT, or whatever their successors are, would start getting on them about shipping filled pressure cylinders. Next new cylinder I get, I'll stick a regulator with a pressure gauge on it just for curiosity's sake before I fill it.

Stan

Depends on the scale.

I have written allot of stuff here trying to reduce your ignorance. However if you have read what I have posted and are of such little mental capacity as to not understand what has been written by me and in the links I have posted there is nothing more I can do to make you more aware.

Interesting thing I saw with my own eyes..I went with a buddy to purchase a used propane tank one Saturday morning about a month ago. We are under the impression from a source that the tank is left over from a tobacco bulk barn operation. When we get to the place, I could not believe my eyes! It turned out to be a guy who recycles used propane tanks, and he had at least a couple acres of tanks of all shapes and sizes, from camper tanks to multi-thousand gallon ones. As we got out of the truck, we noticed several tanks about 100 feet away with 3 inch holes burned in them with a cutting torch, just sitting there slowly burning off the residual fumes in the tank. Needless to say, this made us rather uneasy. Upon talking to the guy, he told us he had been doing this for over 20 years, and had never had an injury or serious incident. He said as the first penetration is made, there is a whoosh from the tank, then it subsides to a slow burn. They do this all day, every day. My buddy bought a used 350 gallon tank from him for $100 and we went on our way. 123 tanks were $30, and 100 pounders were $10, He throws a regulator in on the deal if he has one at the time. I checked with a local gas company about him and the response was "Yeah, he does all our excess tanks, and everybody else's around". I asked the requirements on them filling a tank like that on home delivery, and all they required was a bill of sale or a receipt to prove ownership of the tank, which around here also gets you a 5 cent discount per gallon. As a side note, I purged a 123 gallon tank and used it with a relief valve and a bottom drain for an extra capacity air tank on my sandblasting rig for about 5 years with no problems. The mercaptan smell went away after a little usage. Sandblasting puts out large amounts of static electricity, also.

RJ

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