Filling gas bottles.

[Rigger Mortice]

I’m sure there will be howls of disapproval from some quarters but, following the threads about DIY filling of gas bottles, I thought I would do a little experimenting. This summarises what I have found so far;

1. Thanks to VicS (I think it was him) who gave the initial lead. He recommended getting components from www.BES.co.uk. I found their prices to be good and the service quick and efficient.
2. There is a brief but helpful write up in Nigel Calder’s book and a fair number of websites give information on the process.
3. You need the right adapters on both cylinders. It is not advisable to fill via regulators; they are not designed to do this job.
4. I used high pressure hose assemblies, made up with proper crimped fittings. These are designed to work at up to 17.5 bar. Low pressure hose has a maximum working pressure of 50mbar. The difference is so great that it was an easy decision which to go for.
5. For filling 904/907 cylinders I used BES part number 16643
6. For the supply cylinder, which was a 15kg bottle, I used a 16642 clip on adapter. Other bottles may need a different adapter.
7. Connect both bottles with a 16712 hose. Take care with the hose; the sealing rings in both fittings have a habit of falling out.
8. The procedure was to connect hoses and adapters. Fit onto the supply bottle, and then briefly open the cock at the other end to purge the line of air. Fit the assembly onto the bottle that is being filled.
9. Turn the supply bottle upside down and place it so that it is higher than the bottle which is being filled.
10. Turn the cock on. (Obvious really!)
11. Nigel Calder says that it is a slow process. He is right. I was surprised that it took about 40 minutes to fill the bottle.
12. Weigh the bottle to make sure that it is not overfilled. I deliberately left mine slightly under filled.

Result. Easier than I expected.

Savings. The 15kg gas bottle cost me £33. A refill of the 904 cylinder (1.8 kg) would have cost £22 at my local supplier. It cost me £4 to DIY.
A 907 bottle would cost £6 to fill.
The bits cost £17+VAT and delivery.

Conclusion. The small cylinders are so ridiculously expensive this pays for itself in no time at all! I’m going to do a bit more work and, frankly, I need to also check if this is legal, but I promise that it won't be done when I'm parked near you!

All offered in the spirit of sharing information, If you don’t want to try it then I really don’t mind!

 

[ProDave]

Im not sure if it is "illegal" but it is certainly against the hire terms of Calor and probably most other gas suppliers.

I'm not sure I would want weight to be the only means of ensuring the receiving bottle is not over filled. What about putting the receiving bottle on it's side. Would that ensure it would never get more than half full?

Even better savings can be had if you use 47Kg bottles to fill from, though standing them inverted, above the receiving bottle is no trivial task.

 

[saltylegs]

first I can not recomend this practice.
but weighing the cylinder is how the gas suppliers do it, dont forget to take the tare weight into account (empty cylinder weight) only use butane for butane cylinders and propane for propane cylinders
AND PLEASE NEVER DO THIS ONBOARD.

 

[Rigger Mortice]

first I can not recommend this practice.
but weighing the cylinder is how the gas suppliers do it, dont forget to take the tare weight into account (empty cylinder weight) only use butane for butane cylinders and propane for propane cylinders
AND PLEASE NEVER DO THIS ONBOARD.

I wish somebody would give a considered reason, rather than a reaction, for not recommending this.

Yes, I took the tare weight into consideration. It is conveniently stamped on the cylinder. I also checked it.

The consensus appears to be that it is OK to put Butane into Propane cylinders but not vice versa. (Liquid Propane being at considerably higher pressure than Butane). I can't however see any reason why anyone would want to swap the two different gases.

Of course I won't do this on board. If I could store a bigger cylinder on the boat then I wouldn't need to fill a small one!!

 

[Heckler]

I wish somebody would give a considered reason, rather than a reaction, for not recommending this.

Yes, I took the tare weight into consideration. It is conveniently stamped on the cylinder. I also checked it.

The consensus appears to be that it is OK to put Butane into Propane cylinders but not vice versa. (Liquid Propane being at considerably higher pressure than Butane). I can't however see any reason why anyone would want to swap the two different gases.

Of course I won't do this on board. If I could store a bigger cylinder on the boat then I wouldn't need to fill a small one!!

Take no notice of tooth suckers, suppliers weigh the gas in, how do I know?
I know a man!
Stu

 

[saltylegs]

I wish somebody would give a considered reason, rather than a reaction, for not recommending this.

Yes, I took the tare weight into consideration. It is conveniently stamped on the cylinder. I also checked it.

The consensus appears to be that it is OK to put Butane into Propane cylinders but not vice versa. (Liquid Propane being at considerably higher pressure than Butane). I can't however see any reason why anyone would want to swap the two different gases.

Of course I won't do this on board. If I could store a bigger cylinder on the boat then I wouldn't need to fill a small one!!

its not just a reaction to your post.
I have had to pick up the bits (literaly) after other people have tried this.
I'm not an" elf an safety" freak, but. please just don't encourage those with a little knowledge to try something when they dont know what can happen when the dirt hits the fan.
This isnt meant to be a downer just beware of the possible effects of ones own actions.

 

[Rigger Mortice]

I have had to pick up the bits (literaly) after other people have tried this.

Yes, I've seen the after effects of a gas explosion at close quarters. It was in entirely different circumstances and those that caused it were lucky to escape. However, let me press you on what you saw...........not the gory details but the actual cause of the problem.

I've read lots of people saying "don't do it", but I've seen no reports (press, H&S or anything approaching an official report). Nowhere have I seen anything which explained what caused the problem. I'm not saying it doesn't exist but that I've not seen anything.

It seems to me that the main problems are likely to come from explosion or rupturing (due to the pressures involved) but both of these can be managed.

Without more detail it is difficult to know what to make of your advice. If the guy was smoking, well.....what did he expect? But if there was something more fundamental then it would be useful for people to know.

 

[prv]

This isnt meant to be a downer just beware of the possible effects of ones own actions.

It would help people be aware of those possible effects if you could explain what they are, and (if applicable) how to avoid them. Since you seem to have some specialist knowledge.

Pete

 

[Graham_Wright]

Anything that reduces the cost of sailing is always welcome.

Safety issues I suppose are two fold;- pressure and risk of ignition.

Bear in mind that gas bottles are routinely filled from others in various situations. Dive clubs decant from high pressure storage tanks into dive cylinders and the pressures here are around 200bar. Anybody who has seen a high pressure accident will be aware of the danger. My tig gas supplier does the same with argon at 230bar. Safety is down to awareness and proper engineering. Both seemed to have been addressed by the OP.

Fire and explosion risk are probably far less a worry than gas on board. In an open air environment, leaked gas can safely escape and the risks are arguably less than handling petrol. I once emptied an on board tank little by little and (stupidly) added each jugful to a bucket on the dockside. It took around quarter of an hour for the whole 2 gallons to evaporate. Thankfully no casual passer-by discarded his fag end in my direction.

Taken to its conclusion, is there a possibility of incorporating gas storage as a permanent tank just as with propulsion fuel? In the middle of trying to solve the problems of gas bottle storage to satisfy my and my surveyors concerns I can see advantages in not having flexible connections and movable tanks. The safety issues seem to have b een satisfied for cars although I accept there is no inherent gas trap in their road environment.

 

[ghostlymoron]

11. Nigel Calder says that it is a slow process. He is right. I was surprised that it took about 40 minutes to fill the bottle.

The filling rate is proportional to the pressure difference so initially it will fill quite quickly but as the receiving bottle fills up, the differential is less hence the rate slows down.
If you put the receiving bottle on some scales, you can see how the rate varies.
Great posting BTW. Could result in severe downturn for overpriced Camping Gaz. I don't think its illegal but must admit that I've never read the 'hire agreement' supplied with Calor cylinders - has anyone?

 

[Ubergeekian]

Taken to its conclusion, is there a possibility of incorporating gas storage as a permanent tank just as with propulsion fuel? In the middle of trying to solve the problems of gas bottle storage to satisfy my and my surveyors concerns I can see advantages in not having flexible connections and movable tanks. The safety issues seem to have b een satisfied for cars although I accept there is no inherent gas trap in their road environment.

I can't see any reason why not ... except that you'd need waterside filling points to make it worthwhile.

 

[Graham_Wright]

I can't see any reason why not ... except that you'd need waterside filling points to make it worthwhile.

Or you could still bring your own biggie in the back of the van.

Not much use for away from home though.

 

[ProDave]

Just a few more thoughts on this.

One of the bigest dangers of DIY gas bottle fill has to be overfill. If there's too much (liquid) gas and too little "space" then the risk of over pressure is great.

I'm not totally convinced of just weighing the amount of gas as being adequate precaution. What are youe weighing it with? bathroom scales is my guess in 90% of cases. Do you trust their accuracy? I wouldn't. If that were my only way of preventing overfill, I would want a VERY large safety margin, like fill until your measured quantity of gas is 2/3 what it should be.

Another "problem" is the liquid gas in the fill hose. You don't want to be uncoupling the fill hose when it's full of liquid. So sugestion is once transfer is complete, shut off the donor cylinder, but leave the receiving cylinder valve open. Keep it like this for some time to allow the liquid to drain down from the hose into the receiving cylinder before shutting the valve and uncoupling the hose, now only containing gas.

My last concern is the condition of the receiving cylinder. When a cylinder goes back to it's owner for refil, it's inspected and pressure tested. I can forsee a cylinder being refilled lots of times over a number of years without checks could become old, rusty and unsafe.

 

[ghostlymoron]

Good point about liquid gas in the fill hose. You could put a 'purge/empty' valve in your system. Does the OP find it a problem though?
There's several vids on youtube they all seem to use metal (copper?) pipe not rubber.

 

[pampas]

Interesting thread. What medium do they use for pressure testing. Same gas?

 

[tilmansailing]

This could be very dangerous!

There is an apochryphal (?) tale of people heating the delivery cylinder (with a blow lamp) to get the last of the gas out! Don't even think of it.

 

[kieronriley]

gas refill

down in new zeland i was surprised to find that you can take your gas caister into a garage and buy just what you want i.e five pounds if thats all you want will we ever be able to do this.seems like a good idea to me.Kieron

 

[Steve_N]

Just a couple of points to add to the discussion (from a regular cylinder refiller).

Camping Gaz cylinders are purchased outright and not hired - they are your property so you are not breaking any agreement by refilling them.
Although Calor (and many other companies) do have a hire agreement that you sign upon hiring a bottle, I'm not sure if those terms could be applied if you haven't signed the agreement? I have 8 or so Calor bottles here, acquired from various sources, and have never signed anything.

I believe that the rubber high pressure hoses are not designed to carry gas in liquid form. They have no problem with the pressure, but I've read somewhere that the liquid will degrade the materials over time. I use one, but I'm keeping a very good eye on it.

Gently warming the donor cylinder does indeed speed up the transfer markedly. Blowtorches no, but a kettle of hot water works wonders.

 

[Ubergeekian]

One of the bigest dangers of DIY gas bottle fill has to be overfill. If there's too much (liquid) gas and too little "space" then the risk of over pressure is great.

Since you have a saturated gas/liquid mix in the tank, pressure is dependent on temperature and nothing else. As long as there is a some gas there when you fill, and you don't pump it, I can't see how overpressuring could arise. When I fill my car with LPG it is pumped, so the fuel in the tank warms slightly and the consequent pressure increase shuts off the pump at about 85% full: less if filling from near empty, more if it was almost full when I started.

Another "problem" is the liquid gas in the fill hose. You don't want to be uncoupling the fill hose when it's full of liquid. So sugestion is once transfer is complete, shut off the donor cylinder, but leave the receiving cylinder valve open. Keep it like this for some time to allow the liquid to drain down from the hose into the receiving cylinder before shutting the valve and uncoupling the hose, now only containing gas.

Good idea, but as long as you don't let it squirt on flesh - or smoke - a tube full of liquid propane isn't a particular problem.

 

[Bobobolinsky]

My last concern is the condition of the receiving cylinder. When a cylinder goes back to it's owner for refil, it's inspected and pressure tested. I can forsee a cylinder being refilled lots of times over a number of years without checks could become old, rusty and unsafe.

Give over, it's not inspected and pressure tested, on a refill. The codes requires it to be done at a maximum of 14 years, usually at 10 years when the pressure relief valve needs replacing.

There is no illegality about refilling a Camping Gaz cylinder, as Camping Gaz are the only company in the UK that actually sells you the cylinder. The cylinders are filled at Calor Gas in Bury St Edmunds, who are contract fillers to Colemans.

The one thing that I would suggest is that when you have done the filling, to spray the top of the cylinders with a leak test liquid (at least brush with soapy water)
Sometimes the valves don't seat properly after refilling. If they are leaking, you can push the valve down with a screwdriver, and let it pop up again