Filling empty propane cylinder from another full cylinder

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StevenJMorgan

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Local gas service people refuse to fill my boat gas bottle because it is not one of theirs (location UAE), I have up to now managed to convince by slipping a few notes but this is getting harder and harder.

Local bottles won't fit into my gas locker so this is a problem. Can I buy a local bottle and rig something to fill my bottle from the local bottle...

I know this sounds dodgy but is it possible.

Thanks
 
I would not even think about doing it!! /forums/images/graemlins/shocked.gif

It would mean transfering the liquid component and not the vapours which is where you usually 'tap off' the fuel.

Where were you thinking of doing the decanting of the fuel, on the quay-side or on board your boat?

The UEA is warm and dry part of the world and static discharge is a huge risk and this would need to be taken into account.

The explosive power of propane and butane is considered to be like a mini-nuke and there would be nothng left of you or your boat if it went wrong /forums/images/graemlins/confused.gif

DON'T DO IT - DONT EVEN THINK ABOUT DOING IT!
 
Join the new and old cylinders together with a pipe (no regulators) and let the liquid gas flow to the bottom one. Cylinders need to be of the same size.
 
The pipe needs to be high-pressure stuff intended to be fitted before the regulator, not the type that you fit between the regulator and your cooker.

The best way is to hang the reservoir bottle upside down above the fill bottle. Then open the valves and just let it happen.

Many bottles have a device that prevents them from being over-filled but I believe that Camping gaz, for example, does not. So to be certain, as has been said above, fill from a bottle of the same size. In practice this might be a pointless exercise, so if filling from a large bottle to a small, check-weigh the bottle being filled to the value marked on it.
 
If filling from a larger bottle put the bottle you are filling on some bathroom scales. electronic digital are best and stop filling when weight gate to capacity. Most LPG is sold by weight.
 
Please take the reply from StevenJMorgan above seriously, the process you intend is dangerous.
However if you are determined to proceed then :-
As stated above - The pipe needs to be high-pressure stuff intended to be fitted before the regulator, not the type that you fit between the regulator and your cooker.
Make sure your personal insurance is as you wish it to be, and do not involve others.
In preparation you could make the empty (receiving) bottle cool by wrapping it in a towel and keeping it wet and in the shade. At the same time get the full (supply) bottle warm by leaving in the sun.
In an open area ashore (not on the water) where you will not harm others or property.
Connect the two cylinders with no regulators.
Before turning the valves on make sure the supply bottle is upside down, and the receiving bottle the right way up, so that liquid is transferred rather than gas.
Make sure the receiving bottle is maintained at a cooler temperature than the supply bottle.
Keep the receiving bottle tightly wrapped in a towel and keep it wet, to keep it cool.
Only differences in pressure will make the transfer possible, gravity will not do it.
As the liquid transfers liquid in the supply bottle will have to evaporate to fill the vacant space, this produces cooling. At the same time gas in the receiving bottle will have to condense to make space, this produces heat.
The transfer will only continue while the receiving bottle is cooler than the supply bottle.

DO NOT OVERFILL THE RECEIVING BOTTLE, it must not contain liquid only, if it does as the temperature increases it will burst. Even if it does not burst you will probably have an explosion when you first use it becase liquid gas will be supplied instead of gas. If you think this has happened then reverse the process for a while.

When you have finished then turn the supply bottle the right way up and leave them both for a short while with the valves still turned on and keep the connecting pipe up in the air. Hopefully this will drain any liquid from the connecting pipe and replace it with gas, so that when you turn off the valves and disconnect then only a small amount of gas will escape.

I have never done this and I do not intend to try.
 
Have you given any thought to making a container to house the bottle on the side decks.
If you do decide to try to refill your existing bottle let me know in advance and I will try and see you and give you a wave when your orbit passes over London.There is always a spare berth on the Internationl space station.
 
We fill cylinders regularly ....

We do all the analysis for Latvian Propane Gas ... and we use either double ended valved ASTM cylinders ... or bog std Red ballons from local Propane station.

But we do it in controlled conditions and with steel braided reinforced hose.
Remember that the ballon contains liquid under high pressure to maintain its liquid form ... and also vapour above.
You will not be able to get enough liquid across to really fill the empty ... as temp, expansion and "freezing" of pipes / valves etc. can occur.

Finally it is a dangerous practice to do and I would advise anyone not practised in the art to not try. My guys are trained in it ... probably more than the Gas Station guys you have met.

My advise is to bite the bullet .... use their cylinder and fix it outside the locker ... keeping your old cylinder for when you get to more amenable filling station ...

If anyone wants an idea of the destructive power of a ballon .... ask BOC why they fitted derricks to their trucks .... after an office wall was destroyed by a cylinder going off and "flying" ... and also think on if it catches light .... the BOOM will be heard for miles and bits of surrounding area will be raining down ....
 
Yes - I am sure it is very dangerous - but was common practice in many villages in Africa. Perhaps because of third world attitudes to life expectancy ?
Ken
 
I disagree. It is POTENTIALLY dangerous, which is not quite the same thing. Provided proper precautions are taken it is perfectly acceptable to do it. It may have been common practice in African villages but I can tell you that it is widely done in France, Holland, Spain and Portugal now.
 
What a load of rubbish George! As long as the cylinders are under pressure then the propane will remain in liquid form and will flow according to gravity (liquid flows downhill). The transfer of the contents is made by liquid transfer but there will be a small amount of gas present. Gas transfer is very little and largely negligable when you have hot and cold cylinders, as well there will be a cooling effect when the gas expands which can complicate and negate matters. There is little if no turning to vapour and condensing again while the pressure and temperature remain constant. Forget the warming and cooling actions that just complicates the process, is generally ineffective and slows things down. You will note that in commercial operations it is liquid that is being transferred. In effect the Gas station is the BIG cylinder (a pump is used instead of gravity) and your gas bottle is the SMALL cylinder. Keep both cylinders as cool as possible. There is no more likelyhood of explosion than there is in the original cylinder, unless gas is allowed to escape into the air and ignites somehow.

The donor cylinder should be upside down and above the receiver cylinder. Turn on both the cylinders valves. The size of the containers is not relevant except that receiving to fill up the cylinder, the receiving cylinder should be smaller than the donor cylinder. Liquid will stop flowing when the receiving cylinder is full and will containing some propane in gas form at the same pressure as the donor cylinder. When you think that the liquid transfer is finished you can return the donor cylinder to the upright position and pour a little liquid back by upturning the receiver, then leave both cylinders still connected and in the upright positions and leave for awhile so that gas forms above the liquid in both cylinders, gas pressures equalize and liquid flows out of the connecting tube. Then turn off both valves and remove the connecting tube. At this stage there will be a small escape of propane gas so be careful.

If you want to do things properly weigh the receiving cylinder to make sure that the proper amount of liquid is not exceeded. If you have too much, then you do not risk explosing through too high a pressure but risk liquid coming out instead of gas. It is important to maintain a gas head above the liquid in your cylinder and that is why you do not run your cooker etc with the cylinder on its side or upside down. And this is why the supply valve is at the top rather than the bottom.

If you are happy with using the purge valve in the receiving cylinder then you can use this to speed up the process and turn it off when (or if) liquid starts to emerge. The purge valve has a feed tube which goes down to the ideal liquid level, and thus when liquid emerges then you have reached the safe head. (It is generally not used commercially nowdays as it risks gas escaping and commercial operators weigh the cylinder liquid anyway. The proper weight determins the liquid level.) But be careful as this procedure is releasing propane gas into the atmosphere and there may be a risk of ignition under some conditions thus fire or explosion if the gas is trapped in a small enclosure but you would have likely breathed too much gas before then and likely to be dead.

However problems and difficulties do occur as changes to the technology are designed to prevent you doing this sort of transfer. Anti-syphon valves are being fitted internally and new external valves are designed to not allow gas/liquid to flow, unless a proper regulator is attached which will prevent the transfer operation. The external problems can be overcome but I am not too sure that you can bypass the internal anti-syphon valve.

If it was me then I would make and effort to get a new cylinder that can be filled and is of the appropriate size, and/or else reorganize the storage space. Some of the new aluminium cylinders are designed to run on their side and may solve your space problem. I much prefer kerosene for safety and availability but that is another argument.

Good luck with the operation.
 
The Calor Propane website says the following:
Cylinders containing Calor Propane are designed to give liquid
or vapour offtake.
• Vapour offtake must be used in the vertical position.
• Liquid offtake must be stored and used in the position
indicated on the cylinder.

You can get refillable cylinders, which you remove and take to a supplier, eg a vehicle LPG station. One of the standard sizes might fit the available space.
Or you can buy a LPG transfer pump (about £80 on eBay). These are for transferring LPG between vehicles, or from bottles to tanks and v.v.
 
If you must do this check the tare weight of the bottle .It should also have its filling capacity stamped on it some where.When filling weigh the bottle then subtract irts tare weight = weight of liquid in bottle.You will have to turn the botltle you are filling from upside to get liquid out.Helps to put bottle you are going to fill in the freezer.DO NOT OVER FILL.Hydrostatic expansion=big explosion
 
Why not do a proper job and just increase the size of you gas locker to accomodate the larger bottles. Failing that have them secured on a small platform on the transom so you can merely dispense with the local bottles when you move again>

For what its worth I would not even think of doing the work myself.

Its not that one could be killed doing it , transferring, but think of the paperwork your widow would have to complete for some other poor b8gger nearby who gets a 15lb weight land on his head from 100 feet up.
 
are you guys living in the real world. filling a bottle from another is a definate NO NO . do you understand that the inclusion of air into the cylinder you are filling is a Bomb. and as so many of you are safety concious and have fitted flash back arestors on your propane tanks(Not) . Anyway go ahead but please post your boat name and mooring so I may Steer clear.
 
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