Refilling small propane cylinders

I ALWAYS inverted my tanks. The big tank will sit nicely on its collar on a wood picnic table, with the smaller tank at a right angle.

I really never felt that I got a "full" fill out of the big tank, but it was pretty good. Also, putting the small tanks in the freezer for an hour or more previous is good, too.

I refilled a lot of canisters, and figure I saved a lot of dollars. It DOES take time and effort, though. Steve

I would assume once pressures in both cylinders equalized, then no more flow would be allowed. and your really only getting gas not liquid.....chill down receiver tank or heat supply tank in a tub of hot/warm water and see if it increases how much flow you get.. I seem to recall when I had a brand new 100 gal tank filled the first time it was necesary to "bleed" out any trapped air etc. Perhaps if you depress the shraeder valve after transfer slows or stops would allow a purge or sorts, and decrease in tank pressure and allow for more LP to flow in. Isn;t liquid what you want in the tank. I donl;t htink a tank full of just the gaseous portion is going to amoaunt to much of a supply, so odds are your gonna have to invert the supply tank to get liquid as they don't have a dip tube in them.

Have fun be safe

Big tank upside down, so *liquid* is transferred! It will work with it right side up, but only if the big tank is warmer than the small one and will take forever (the propane evaporates in the big tank, passes as gas to the small, and condenses there).

Even when upside down, the big tank should be warmer than the small one, so the vapor pressure there is greater and will force the liquid through. It could drain by gravity, but the openings are so small that it's impractical.

Note: "big one warmer" can mean heating the big one or cooling the small one. And keeping it that way.

Getting the small one totally full can be done, but shouldn't. There should be "head room" in the tank for expansion with temperature rise. The standard is 20%, IIRC. If you wanted to be fussy, you could fill by weight, but that would mean some back-and-forth to the scales.

HTH, Bob

You misunderstand the process.

You have to vent the receiving tank.

You have to invert the tanks such that liquid is being fed into the adapter.

You have to waste (by venting) a lot of flammable gas to overcome the thermodynamic work needed to move the stuff from one place to another.

I used to have a refillable propane bottle that had a vent you opened with a wrench. Worked great.

You can completely refill disposable bottles if you can get the vent to work.

I never do. It's not necessary if the small tank is cooler, as gas there will condense if the pressure exceeds the vapor pressure for that temperature.

Bob

I just use the 4' hose meant to connect the table top barbecue to the

This will not work with the new OPD valves because they are designed to NOT release liquid! To refill a standard lantern/torch size propane tank: Invert a large tank (40 # or larger with no OPD) on a bench so you are gravity feeding only liquid propane. Use a tire valve wrench on a long handle to open the relief valve on the smaller container. It is a standard Schrader type valve on one side of the top that extends about 2" down into the tank. Set the small container vertical and brace in position. Connect the refilling hose. Open the valve on the large tank. Fill until liquid starts coming out the relief valve. Close the large tank valve then holding the wrench with a gloved hand close the relief valve Remove the fill hose.

The small tank will be about 80% full which is the original safe fill level to allow for thermal expansion.

On Sat, 7 Jan 2006 17:34:40 -0800, with neither quill nor qualm, "Steve B" quickly quoth:

I thought the OPD valves on new tanks prevented overfilling OR any possible liquid propane discharge. Am I wrong? I'd rather refill my old 1 pound tanks if possible.

-- "Not always right, but never uncertain." --Heinlein -=-=-

Well, you will notice past tense. It shows how long it has been since I refilled any of the tanks.

BTW, someone here said if you label the old tanks "FOR CUTTING ONLY" that you can get them refilled.

Steve

Just use a salt/ice bath to cool the little guy, and no venting is required. If the big guy is in the sun, so much the better.

But remember - it is ILLEGAL to TRANSPORT a refilled cyl not specifically designated as refillable.

I wonder what exactly the people that wrote up that particular law were thinking. I mean, really, it's not like there's a flag on the cylinder that pops out to rat out the refilled ones. And nobody ever lies to an authority figure when asked a question like "Have these cylinders been refilled?"

Not that I can recall ever being asked.

Yeesh!

Cheers Trevor Jones

wrote

This has been beaten to death. TRANSPORT means for a licensed interstate carrier to take the refilled goods over a state line for pay. Intrastate is covered by state DOTs. Private citizens are not hassled because there is very small danger, and when was the last time you saw them stopping traffic on the Interstate and looking for refilled one pound propane canisters. And how would one tell they were refilled?

Sheesh.

Steve

Exactly. It is activated by internal pressure. It looks like a Schrader, but that is as far as it goes. Try one that is nearly empty with some needlenose pliers.

What good would the safety device be if increasing pressure only seated it more? You are 100 % correct, sir.

Steve

We have probably 6 of the old style 20 pounders. As a commercial entity, we've never had to justify their use. We use one 20 to power our Drott Go-Devil, and dad refills his camping bottles as well.

Why not get one of the adapters for stoves and run the torch off the big bottle? Never done it but would think it would work. Karl

by

Back in my steam tug modeling days I chopped a standard bottle down so it would fit in the hull. Refilled it regularly and hauled the boat to meets all over the SE. At several meets there were state boiler and fire inspectors checking all the installations before we could fire up. A lot of the other propane fired boats that came from all over the country had similar setups. No inspector ever called us for "transporting" and we were refilling right in front of them.

Here is some advice from someone who does this a lot. Warm the big tank. OPD or not, it will fill the small one. You may not get the OPD tank to fill the small tank when the OPD is nearer to empty. Chill the small tank in the freezer. It works on pressure differential only, and liquid comes out when the big tank is inverted. It is best to weigh the small tanks to get it filled correctly. New ones weigh 2 lbs. Empty weigh 1 lb. Weigh yours to be sure where you are at with a new one / empty one. Put the adapter on the big tank, tightly. Screw on a 1 pounder. Invert the whole works, open valve and wait one minute. Close valve, unscrew the small tank in the upright position. Should fill it damn near to 2 lb weight. You may have to re-chill the small tank again (and repeat the process for 10 seconds) to get the last 10-20% in (80% full, 2 lbs). This is as full as a new one. I have refilled some (super size) 2lb, 1 or 2lb, 2 oz. Just don't bring them into a warm environment (100 F), or they may bleed off. Be careful ! ! ! If you are not sure what you are doing, don't do it. David

I had one of those. Under twenty bucks, IIRC. A very economical way to go. Plus, you can buy "trees" and run more than one thing at a time, like stove and lantern.

STeve