Filling propane bottles.

[Guest]

er in other countries that is. In the UK its easy, simply hand in the old empty bottle and receive in return a full one, but in other countries I read that it is most likely they have a different fitting so the exchange scheme is a non starter. Also from reading I find that a number of possible ways out of this problem exist.
1) adopt the countries solution, new bottles and new regulator. Pricey and probably impractical unless long stays in a given country are planned.
2) find the local bottle filler and hope he has the calor fitting. This seems wildly optimistic. Iwouldn't even know where a bottle fillier exists in the UK.
3) Buy a local bottle and decant the contents. This seems best, particulary from the stance, the less one knows of a subject the easier it seems, but how easy is it?

I can see that the full one needs elevating and even being enclosed in a black poly bag to give it a little heat would help. The empty one being lower to allow gravity to do its bit, also I can see that cooling it would help lower its pressure but perhaps by some almost trivial amount. Then what about fittings?

I'm already wondering where to get a Calor fitting which allows a "full bottle pressure" connection. What does one of these look like and who sells them?

I'd welcome any wisdom on the above. Over.




<hr width=100% size=1>Barry (yacht Mithril)

 

[wooslehunter]

Decanting will work but not well.

Since we effectively have a closed system, I'm not sure that gravity will have much effect. The gas is heavier than air so it will sink in air. There's no air in the bottles, so nothing to sink in.

If you simply connect the bottles and open the taps, the pressure will equalise. Hence you'll get both bottles half full. Once the UK bottle is empty you can decant again and get quarter full bottles. You can continue but with diminishing returns.

Temperature will have an effect but remeber that as gas expands in heats up. Therefore the UK bottle will tend to heat up as it fills and the other will cool. Fill slowly by partially opening the taps and leave to cool/heat for a while once pressures are equalised.

That's the physics. This is a common practice when filling diving cylinders from an air bank but you generally have a storage bank far larger than the cyclinger and it's also at a higher pressure.

Maybe someone whose actually done this can comment on the practicality.

Dave

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[vyv_cox]

I thought the propane was liquid in the bottle? Liquid at the bottom, gas at the top. So surely decanting is simply a matter of inversion?



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[Guest]

Thanks Dave, I can understand the physics when we are talking air but in a propane situation we are talking liquids (I think) and so gravity might work. Naturally I've got zero practical experience.

<hr width=100% size=1>Barry (yacht Mithril)

 

[MainlySteam]

That is absolutely correct and LPG is regularly decanted professionally. I have seen quite a few accounts of cruisers doing it too, in fact not long ago I saw a very detailed account but do not recall where. I have also seen "LPG for decanting" advertised in less sophisticated countries.

I would not and have not done it myself, but the basic essentials are:

Connectors and hoses that will stand liquid pressure (propane vapour pressure not butane!)
Tank to fill lower then the other.
Plenty of time
Gloves to avoid the risk of freezing in case you have a leak (Goggles might be useful too)
Both tanks on a grounded surface so you don't go bang from static ignition if you have a leak
A great deal of courage or a great deal of ignorance
Some jurisdictions it is an illegal practice

Do not know how useful a fire extinguisher would be - if you have a problem things will probably happen pretty fast.

Many years ago, people working in the LPG industry were shown a film called BLEVE ( we had to see it, and others, at least annually while working on a large LPG infrastructure project). It will put you off forever.

Take care

John

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[wooslehunter]

Yup - forgot it's a liquid.

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[JerryHawkins]

Good website for advice/parts

Have a look at: http://www.calormarineshop.co.uk

This site has advice on installation, problems with incompatibility when travelling around the world and parts you may need.

Cheers,

jerry

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[Shanty]

If you can get hold of a copy of Nigel Calder's book "Boatowner's Mechanical & Electrical Manual, he describes the process of refilling one cylinder from another - p458 in my second edition copy


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[Guest]

decanting does work but slowly, need to make up the fittings, ie left hand theread tube to left hand thread tube with flexi pipe joining, calor flexi pipe is designed to take the full bottle pressure in case of regulator failure and in theory can be used. i would make up the fittings before hand in the uk to take with me. calor do a cross over to go to camping gaz in the case of butane.
nigel calders book ( i am pretty sure) has a picture of the very system in operation, the other thing i would say that in the majority of third world countries the regulators are thet cheap that it is not an issue to buy one in the country being visited, and in the med a calor crossover will get you away.
as for a full bottle pressure fitting, i would unscrew the left hand thread bit out of the regulators and just join them with calor tube, wedge the full one upside down above the empty one and the liquid gas will trickle thru the fitting. it wont work if you try to do it thru the regulator, by the way do you really mean propane? or are you mixing gas and butane and propane up

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[freedom44]

Firstly, I thought most UK boats had a butane system, not propane, but whatever, the system is the same.
I have an american built boat which has large fitted aluminium propane cylinders which I am loath to get rid of.
I bought in america from West Marine the fitting to the cylinder, and bought another in Uk to fit a normal UK propane cylinder.
I raise the full cylinder and palce it in a dustbin of hot water.
The receiving one is below which I cool with a hose of water.
Turn on the taps . A satisfying hissing!!
Weigh the cylinders so as not to overfill.

In america you just go to the local caolmerchant/ LPG depot and the fill them on the spot. Nearly impossible in UK and Europe due to the bureaucrats and the local monopoly suppliers not allowing you to swap cylinders.

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[ccscott49]

When in Portugal, I just bought the regulator and bottle, less than a re-fill in the UK! The regulator is the same in spain, (repsol) But they will not refill portugese identical, bottles (slightly different handles) Buy a cylinder from a flea market, or steal one!! No I didnt say that did I? The refills are cheap. I will do the same when in Italy, but may not need to, I carry enough gas (3 x 15 kg) for a year.

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[Anchorite]

Re: Don\'t want to set the world on fire??

I'm a gas engineer and (more or less) know what I'm doing when working with
liquid gases. Here are the pressures involved on a normal summer's day (20° C):
Butane - 1 Bar (15 psi); Propane - 7 Bars (100 psi). The brave man heating
it up in his dustbin (???) will find 4 bars with Butane and 17 Bars (250 psi) with
Propane when it reaches 50°C.
A new cylinder costs about £25: I've never seen a French carboot sale (vide grenier) where there wasn't plenty on offer at a fiver.
Just a thought: would your insurance cover an "unfortunate incident" during an
operation of this nature.

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[MainlySteam]

Like Freedom44 it is easy getting ones own cylinders filled here too (we carry 2 of our own) and much the same all around the Pacific as I understand it. You are not allowed to fill your own cylinders though. There is a description in Calders book on decanting, but again, having worked in the industry I would not recommend the process to casual practitioners.

There is plenty of information on the internet about coping with different countries fittings and exchange systems, this <A target="_blank" HREF=http://www.socal.co.uk/bluewater/bwn20.htm>http://www.socal.co.uk/bluewater/bwn20.htm</A> being just one. It gives within it recommendations for both UK and USA yachtsman travelling to other parts of the world.

Remember that it is much different to siphoning petrol, anything other than a small liquid leak with LPG will suddenly give you an awful lot of vapour which will expand to a large explosive volume. The liquid leak will be driven at LPG vapour pressure (around 8.5 atmospheres at 20C). In normal manual decanting the cylinder being emptied from has a valve which has to be physically held in during the process, so if there is a fitting or hose failure, letting go will immediately stop the flow of liquid.

I do not even like carrying the filled cylinders in my car from the refill station to the marina in case of a valve leak, and a friend of mine who has also worked in the industry is exactly the same - when talking about it one day we discovered that we both carry the cylinders in the passenger compartment of the car to give best chance of smelling a leak before combustion (whether that is the safest or not is pure assumption on our part, but we both had independantly done the same).

It is an excellent fuel, but treat it with respect.

John

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