Hi MH
For clarity can you specify the model of Gaslow system you are considering, because I have just viewed thier site and all I see are 'Calor' type cylinders, which I would class as portable, and thus it is suspect in terms of refiling at petrol/lpg stations.
Clive,
You clearly need to stop the amber nectar before taking to the keyboard - So I ask a question about whether a technician has to be corgi registered to work on a vehicle - it's a valid question - after all they should to work on a caravan or motor home.
By the way it's Fraser Island not Frazer Island - went there in 1993 - can recommend if a little built up now and overrun with Jap Tourists. Sunshine Coast has a lot to recommend it. I take it you be eating out all the time ?? or will your Barbie solar powered ??
You clearly need to stop the amber nectar before taking to the keyboard - So I ask a question about whether a technician has to be corgi registered to work on a vehicle - it's a valid question - after all they should to work on a caravan or motor home.
By the way it's Fraser Island not Frazer Island - went there in 1993 - can recommend if a little built up now and overrun with Jap Tourists. Sunshine Coast has a lot to recommend it. I take it you be eating out all the time ?? or will your Barbie solar powered ??
Gas powered barbie - tho what we had last time was more of a griddle. Superb for fish if you can stand the flies.
And I have never run out of gas.
Don't like lager - tho it does taste better there
If I cannot get a good rioja crianza whilst here - an Aussie shiraz will do.
But a UK brewed "amber nectar" - hardly a angel p*ssing on me tonsils is it.
And I have never run out of gas.
Don't like lager - tho it does taste better there
If I cannot get a good rioja crianza whilst here - an Aussie shiraz will do.
But a UK brewed "amber nectar" - hardly a angel p*ssing on me tonsils is it.
In regard to your technical question about mechanical safety (not legal safty) of filling.
It is important to understand that LPG stands for Liquified Petroleum Gas. This diffentiates from petrol becuase at normal atmospheric temperature & pressure, petrol remains a liquid with a little vapur release but LPG would be a Gas or more correctly a vapour.
To store petroleum gas, it can be eeither chilled or pressurised which causes it to turn to its liquid state, hence Liquified Petroleum Gas rather than Liquid PG.
Another common factor beteen Petrol and LPG is the vapour of both products is heavier than air and as a consequence where there is a release the vapour will tend to pool at the lowest un vented collection point (such as drains etc) for this reason the uncontrolled release of either product should be avoided.
Both products are of course flamable, but only when mixed in the correct proportins with oxygene (usually in air), as a general rough rule of thumb 1 part vapour to 10 parts air will create a combustabale mixture. with the right conditins a mixture will burn very vigerously and be classed as an explosion. It is generally easier to to get LPG vapour to react explosively than pertrol.
When you fill a petrol tank, the liquid entering the tank will displace any vapour in the tank. The petrol vapour will esacpe back up the filler tube and and past the loose fiting nozzle to the air, so filling a conventional petrol drive car will always produce some escape of vapour.
When you fill a Propane tank, the gas is always suplied at considerable pressure. (greater than 6 bar at 20 C) This is needed to transfer the gas in its liquified state but the system is sealed ans thus ther shodl be no escape. When you finish filling the tank, both teh tank and filling systen valves will be closed but there will be a volume between the two isolating systems but when the coupling is released that small amount of gas(or liquied) will be exposed to normal atmospheric pressure and will expand accordingly. (liquified Propane expands to about 270 times its volume at 1Bar)
I conclude that It is likely that there will be less LPG product lost during correct filling procedure than petrol into a car.
In the event of tank rupture or seal failure, the fact that teh sytem is under great pressue will cause fluid to be ejected.The system will always be at atmospheric pressure during filling. thus a tank or seal ruptue will only produce a dribble of fuel.
However, if due to incorrect procedure or faulty equiepment there is a sizeable spillage of LPG, the product is far more volatile than pertol, and thus represents a different set of dangers.
Venting LPG causes a massive temperature drop of the LPG and anything it touches as it rapidly absorbs heat from its surroundings in an effort to vapourise, severe frost burns are a typical concern.
If the escape is from a hose under pressure, then turning of the source does not stop liquefied gas from continuing to esacpe through the damaged section until it drops to atmospheric pressure. You cannot easily stem the flow of LPG from a leak becuas it is stored under pressure, and it will lift off most attempted to patch it.
Hello again MH
Ive just spent a lot of time giving what I hope is comprehnsive and informative answer to a question of yours a few postings above, but I have just read down to this one and -----
Irony of irony, The Gas Safety Installion and use Regulations requier that a competent person undertakes all gas installation tesing repair and removal work except on touring caravans which are specifically excluded! daft isn't it!
However Health and Safety Legislation reaqiures all sytsems are safety checked, and so fitters must be compepetent in installatoin and testing procedures, which basically means Corgi or other reconised approved bodies registerd for the type of installtion they are working on.
Insurance companies are likely to take dim view of a touring caravan gas installtoin not installed and maintained by a Corgi fitter.
I do not know which body oversees the evaluation of competency and registration of fitters for motive power systems.
John,
You raise a really interesting point or two for that matter - firstly it's incredible that a caravan is a fairy basic boxes on wheels that doesn't have anything like a sophisticated suspension set up as a car for instance but over a say 20 year life it will get bumped along all sorts of roads and the connections and joints etc will all be subject to stress and as I pointed out to Clive It would be interesting to see a display of gas safety say a yearly sticker Certificate.
I'm sure Lutz will correct me if I'm wrong but the German MOT test on caravans does include gas condition testing
Second point - personally I find the mechanical services offered by caravan dealers to be very questionable in terms of integrity or value for money. Last summer at a large dealership I saw a brand new van
You raise a really interesting point or two for that matter - firstly it's incredible that a caravan is a fairy basic boxes on wheels that doesn't have anything like a sophisticated suspension set up as a car for instance but over a say 20 year life it will get bumped along all sorts of roads and the connections and joints etc will all be subject to stress and as I pointed out to Clive It would be interesting to see a display of gas safety say a yearly sticker Certificate.
I'm sure Lutz will correct me if I'm wrong but the German MOT test on caravans does include gas condition testing
Second point - personally I find the mechanical services offered by caravan dealers to be very questionable in terms of integrity or value for money. Last summer at a large dealership I saw a brand new van
I have my caravan gas system pressure checked every year and changed the rubber pipes as a matter of course on purchase (it was not new). It then gets a sticker to say that this has been done and the invoice goes in with the log book and makes up its "service history".
The main difference between a car based system and a caravan based system is that the cylinders are detachable and the pipes leading to the caravan appliance can go via connections and "T" pieces so that multiple appliances can be fed from the one source. The caravan system is like a household gas supply - i.e. it really is a GAS in the pipe.
Hence the need to pressure test.
The situation on a car is very different in that the LPG travels to the vaporiser as a liquid. Also, the tank(s) do not have a manual valve. Therefore if the tank is situated within the body/boot of the car (as a cylinder is within a caravan) the pipe must be enclosed in a sturdy outer pipe that vents any leaking gas to atmosphere outside the car.
The pipe on a car takes the LPG as liquid unlike in a caravan that takes the Propane/Butane as a gas to the appliances. In a car, the LPG is heated in the vaporiser and fed to the inlet manifold according to throttle demand.
So the two systems are substantially different.
So please do not take this the wrong way MH, but it is clear to me now that you are equating any gas system with that of a house - hence your comment about Corgi engineers being able to work on Car LPG systems.
Should be clear to you now that a car LPG system as it carries the LPG in a liquid state and then has to provide a graded supply at the inlet manifold according to throttle response engine load etc.
One further query I thought of today is that Liquid Petroleum gas is a mixture of mainly Propane, a fair bit of Butane and a little Methane.
Gaslow state that LPG is Propane which is not entirely correct because LPG is not entirely Propane.
I have never used anything other than one type of calor gas cylinder but thought that if you did need to switch due to winter caravanning, then a different regulator was required? One for Propane and one for Butane.
So what happens when you run a mixture of the two?
Any thoughts anyone?
The main difference between a car based system and a caravan based system is that the cylinders are detachable and the pipes leading to the caravan appliance can go via connections and "T" pieces so that multiple appliances can be fed from the one source. The caravan system is like a household gas supply - i.e. it really is a GAS in the pipe.
Hence the need to pressure test.
The situation on a car is very different in that the LPG travels to the vaporiser as a liquid. Also, the tank(s) do not have a manual valve. Therefore if the tank is situated within the body/boot of the car (as a cylinder is within a caravan) the pipe must be enclosed in a sturdy outer pipe that vents any leaking gas to atmosphere outside the car.
The pipe on a car takes the LPG as liquid unlike in a caravan that takes the Propane/Butane as a gas to the appliances. In a car, the LPG is heated in the vaporiser and fed to the inlet manifold according to throttle demand.
So the two systems are substantially different.
So please do not take this the wrong way MH, but it is clear to me now that you are equating any gas system with that of a house - hence your comment about Corgi engineers being able to work on Car LPG systems.
Should be clear to you now that a car LPG system as it carries the LPG in a liquid state and then has to provide a graded supply at the inlet manifold according to throttle response engine load etc.
One further query I thought of today is that Liquid Petroleum gas is a mixture of mainly Propane, a fair bit of Butane and a little Methane.
Gaslow state that LPG is Propane which is not entirely correct because LPG is not entirely Propane.
I have never used anything other than one type of calor gas cylinder but thought that if you did need to switch due to winter caravanning, then a different regulator was required? One for Propane and one for Butane.
So what happens when you run a mixture of the two?
Any thoughts anyone?
Meant to include the fact that on a car LPG system it is forbidden to have any join in the pipe from the tank to the vaporiser. The pipe must be entire and sited away from the extreme underside of the car to prevent damage from "scraping".
4x4's thus make conversion easy as the pipe can often be run inside a "C" section chassis or on top of a box section chassis.
4x4's thus make conversion easy as the pipe can often be run inside a "C" section chassis or on top of a box section chassis.
Clive,
I think I found a website worth of a bookmark for you
www.stations.gpl.online.fr/
I quite easy to navigate round, what I found interesting was the difference in price for LPG in France - a difference by a bigger margin than the UK I think
Regards
I think I found a website worth of a bookmark for you
www.stations.gpl.online.fr/
I quite easy to navigate round, what I found interesting was the difference in price for LPG in France - a difference by a bigger margin than the UK I think
Regards
Following this convo with interest but interjection Clive,
LPG's are a group of gasses which include Propane and Butane, I don't think Methane is strictly under this umbrella.
(Methane is a colorless, odorless gas with a wide distribution in nature. It is the principal component of natural gas, a mixture containing about 75% CH4, 15% ethane and 5% other hydrocarbons, such as propane and butane. http://scifun.chem.wisc.edu/chemweek/methane/methane.html )
In the UK Propane and Butane are sold entirely separate in red or blue bottles respectivly or more recently together in a 60/40 mix as 'Patio' gas in a green bottle.
Carry on
LPG's are a group of gasses which include Propane and Butane, I don't think Methane is strictly under this umbrella.
(Methane is a colorless, odorless gas with a wide distribution in nature. It is the principal component of natural gas, a mixture containing about 75% CH4, 15% ethane and 5% other hydrocarbons, such as propane and butane. http://scifun.chem.wisc.edu/chemweek/methane/methane.html )
In the UK Propane and Butane are sold entirely separate in red or blue bottles respectivly or more recently together in a 60/40 mix as 'Patio' gas in a green bottle.
Carry on
Thanks for that Gary - I was unsure about the methane bit as well but Rob_Jax on a previous post made it clear that Autogas (LPG) is made up of a fair old mixture of the volatile hydrocarbons. Propane is the main one.
John also suggested that the higher ration of Butane in Spanish LPG could be why my LPG system registers as full if I have any LPG in my tank. The higher amount of Butane will apparently provide a lower residual pressure in the supply tank that is not enough to override the pressure in my cars LPG tank as UK LPG has more Propane.
I have no idea if this is correct but it sounds feasible.
John also suggested that the higher ration of Butane in Spanish LPG could be why my LPG system registers as full if I have any LPG in my tank. The higher amount of Butane will apparently provide a lower residual pressure in the supply tank that is not enough to override the pressure in my cars LPG tank as UK LPG has more Propane.
I have no idea if this is correct but it sounds feasible.
I had a very cold girl ring me from the Alps last winter as she hoped I could find out why her 'full' bottle would not give her any gas.
It turned out she had a refillable bottle (topical!!)and the local service station autogas mix was 60/40 propane/butane, subsequent fills became less and less until she ended up with a full bottle of Butane and no heating with temperature well below freezing. Only answer was to drive down the mountain into warmer climes.
Due to buying a petrol hungry car I have only this week asked a few questions about gassing it up. My limited understanding to date then,(underlined),is UK autogas is 100% propane or near as, it is also the same gas as bulk delivered for home heating, ie Propane, while as we can see it's different on the Continent. This also goes for continental filled blue bottles which I also understand to be a 60/40 mix.
As far as what Johns says,(far be it me to argue!),Butane bottle pressure is around 25psi at a given temperature while Propane would be 125psi at that same temperature, ie, much higher at any given temperature. Does that help?
Hello Gary,
Your are quite right about the relative pressures of butane vs Propane. I only alluded to the Propane as that is the major constituant of LPG for motive power, and it is also the fuel that would be available for refillable portable bottles.
I do not know of any retail outlet that self butane to refil bottles - butane is almost exclusivly used for rental or single use systems, (Cigarette lighter refills being the exception)
Clive,
I thought I've already given an answer to the question of Corgi but here goes again, Just to be clear I asked the question because I didn't know if it was an appropriate qualification after all corgi stands for the Council of Register Gas installers and a couple of other people that I've asked at work said "good point" they didn't know either. I guess if you into gas (as you are so to speak) then you broadened you knowledge base and what seems like a stupid question is a valid one to one with lesser knowledge of LPG systems.
Apart from City Guilds in Gas engineering there doesn't seem to be a really nationally qualification in this area
LPG to me is a group of gasses and confuses the issues, much better to call it one or the other or 'mix'.
What I should have said is Butane takes far less pressure to turn it to a liquid than Propane by about 5:1
Reading back Rob a very experienced chappy was contradicted with the reason given that tanks fitted to cars need to be somehow stronger than portable tanks to stand was it 'more delivery pressure'?, given the above that cannot be true as the pressure is from the compression which is the same for both type containers.
It's also a little know fact that both red and blue cylinders in the two small sizes are made to a higher strength than the rest,(class A). This is to take the knocks they are expected to get in transit and maintain their integrity under extreme conditions. That and the more regular checks made upon them is part of the reason for the higher retail price of the gas within.
With respect of your chilled child!
Her sad experience demonstrates another difference between Butane & Propane. Butane requires a temperature of more than -4C to be able to vapourise at this temp, it is very lazy and will not provide enough pressure to run caravan gas system,in practice it the temperature needs to be about 5C or more so that there is enough heat available from the atmosphere to keep the bottle warm enough to keep the gas vapourising.
Propane has exactly the same operational process but it all happens at about -40 - which is well below normal environmental caravanning & camping conditions.
I have implied that the bottle needs a warm atmosphere to allow it to work - and so it does. As the liquified gas draws the energy to change phase (liquid to vapour)from the heat of the body of liquid. In doing so it actually cools the liquid and the container, which explains the dew ring you see on some bottles when they are used. This change in temperature of the liquid is also used by some gas bottle volume indicators.
If the amount of gas used is great, then the cooling continues until there is insufficient heat left in the bottle to continue the process and the vapour pressure falls.
The self cooling effect is determined by the amount of gas you are using. It is also the reason that Butane only really works at 5C and above because it self cools to a lower temperature. Propane is teh choise of commercial opperators because it will continue to work at all year round. In fact if you see roofing contractors at work you will usuall see ared gas bottle with a layer of frost, because they are using the gas at a very high rate to melt the bitumen.
Where butane and propane are mixed, each gas retains its individual charateristics, so as the temperature drops, the propane will continue to vapourise, whilst the butane remains in its liquid state.
I have seen some people make the mistake of wrapping thier butane bottles up in an insulating jacket - 'to keep them warm'! It actually makes the problem worse, they need to be in free air where thay can absorb heat from the atmosphere.
If you do get stuck with cold weather and butane a short term solution is to pour a bucket of water over the gas bottle. The water will be warmer than the air, and will contain much more heat energy than the immediate air. It will give you enough gas to boil a kettle for the all important cup of tea.- A trick I had to use onteh Norfolk broads one October - A bucket or two of river water provided enough warmth to the gas bottles to get us going. A Similar problem happened with some Scouts. we stood the gas bottles in the stream just behind the cook tent and breakfast was cooked.
Any one for bacon & eggs?
Her sad experience demonstrates another difference between Butane & Propane. Butane requires a temperature of more than -4C to be able to vapourise at this temp, it is very lazy and will not provide enough pressure to run caravan gas system,in practice it the temperature needs to be about 5C or more so that there is enough heat available from the atmosphere to keep the bottle warm enough to keep the gas vapourising.
Propane has exactly the same operational process but it all happens at about -40 - which is well below normal environmental caravanning & camping conditions.
I have implied that the bottle needs a warm atmosphere to allow it to work - and so it does. As the liquified gas draws the energy to change phase (liquid to vapour)from the heat of the body of liquid. In doing so it actually cools the liquid and the container, which explains the dew ring you see on some bottles when they are used. This change in temperature of the liquid is also used by some gas bottle volume indicators.
If the amount of gas used is great, then the cooling continues until there is insufficient heat left in the bottle to continue the process and the vapour pressure falls.
The self cooling effect is determined by the amount of gas you are using. It is also the reason that Butane only really works at 5C and above because it self cools to a lower temperature. Propane is teh choise of commercial opperators because it will continue to work at all year round. In fact if you see roofing contractors at work you will usuall see ared gas bottle with a layer of frost, because they are using the gas at a very high rate to melt the bitumen.
Where butane and propane are mixed, each gas retains its individual charateristics, so as the temperature drops, the propane will continue to vapourise, whilst the butane remains in its liquid state.
I have seen some people make the mistake of wrapping thier butane bottles up in an insulating jacket - 'to keep them warm'! It actually makes the problem worse, they need to be in free air where thay can absorb heat from the atmosphere.
If you do get stuck with cold weather and butane a short term solution is to pour a bucket of water over the gas bottle. The water will be warmer than the air, and will contain much more heat energy than the immediate air. It will give you enough gas to boil a kettle for the all important cup of tea.- A trick I had to use onteh Norfolk broads one October - A bucket or two of river water provided enough warmth to the gas bottles to get us going. A Similar problem happened with some Scouts. we stood the gas bottles in the stream just behind the cook tent and breakfast was cooked.
Any one for bacon & eggs?
Glad you illuminated on the scout story John, I had images of little scouts stood neck deep!! It does remind me though of a 'camp' in Snowdonia not scout but school when the milk kept going off due to the heat. I had the 'bright' idea of standing the crates on the boulders in the mountain stream passing through the site.
All went well until one night the heavens opened and the resultant flood washed everything into the now deep pools below the rocks.
Breakfast and particularly Tea depended on their urgent retrieval and guess who was shoved in first?? Brrrrrr was it cold!!!
Thanks for that John & Gary - it certainly explains and makes sense of the problem I have on first fillup in Spain. Interestingly a friend who regularly drive to Gibralter but prefers to drive thro' France rather that take the Santander Ferry never has a problem.
Could it be that as he travels south the Propane/Butane ratio alters gradually?
Also - I take your point Gary about the name confusion as most people think that LPG stands for Liguid Propane Gas - which of course it can do when applied to the correct colour cylinders!
However Autogas for cars - is also termed LPG, but here the P stands for Petroleum - as the LPG here is indeed a "MIX".
Whatever you do please do not think I am taking the P!!!
Could it be that as he travels south the Propane/Butane ratio alters gradually?
Also - I take your point Gary about the name confusion as most people think that LPG stands for Liguid Propane Gas - which of course it can do when applied to the correct colour cylinders!
However Autogas for cars - is also termed LPG, but here the P stands for Petroleum - as the LPG here is indeed a "MIX".
Whatever you do please do not think I am taking the P!!!
Hello Clive,
Technically LPG always stands for liquefied Petrolum Gas. In reality it can be any petreum gas that can be liquified, by increasing pressure or cooling it.
Pure propane does exsist as a 'test gas'used by appliance manufactures to test an appliance for performance and compliance to the relevant standards. Similarly there are pure versions of most LPGs for the same reasons.
Commercial gasses such as those sold by Calor have to conform to some standards but are rarely pure. they usually contain varying proportins of other Hydrocaron gasses. This is either by design or through the coarser and thus cheaper frationising process that makes the gas.
The mixing of some Propane with butane is quite common to help with lower temperatures, but other Hydrocarbons will also be present.
As for the mix of comercial propane across Europe, there are international standards for particular grades of gas, but as with petrol there can be variations within that standard and between manufactures. Some national standards vary as well, so rather than a gradual change of the mix supplied across to Spain, it is more likely to change at boarders, and with the supplying company.
There are significant differences in the mix of natural gas supplied to homes, so much so that manufactures of appliances wishing to supply accross europe have to arrange for special supplies of test gassess to be able to test thier appliances. In fact some manufactures find they still have make small changes to appliances to make them work and therfore saleable for some EU countries.
To demonstrate how variable gas supplies can be: look inside your caravan refridgerator. You will probably find that it has a printed lable, and on it, it will list the countries and the relevant gas categories that apply.
Technically LPG always stands for liquefied Petrolum Gas. In reality it can be any petreum gas that can be liquified, by increasing pressure or cooling it.
Pure propane does exsist as a 'test gas'used by appliance manufactures to test an appliance for performance and compliance to the relevant standards. Similarly there are pure versions of most LPGs for the same reasons.
Commercial gasses such as those sold by Calor have to conform to some standards but are rarely pure. they usually contain varying proportins of other Hydrocaron gasses. This is either by design or through the coarser and thus cheaper frationising process that makes the gas.
The mixing of some Propane with butane is quite common to help with lower temperatures, but other Hydrocarbons will also be present.
As for the mix of comercial propane across Europe, there are international standards for particular grades of gas, but as with petrol there can be variations within that standard and between manufactures. Some national standards vary as well, so rather than a gradual change of the mix supplied across to Spain, it is more likely to change at boarders, and with the supplying company.
There are significant differences in the mix of natural gas supplied to homes, so much so that manufactures of appliances wishing to supply accross europe have to arrange for special supplies of test gassess to be able to test thier appliances. In fact some manufactures find they still have make small changes to appliances to make them work and therfore saleable for some EU countries.
To demonstrate how variable gas supplies can be: look inside your caravan refridgerator. You will probably find that it has a printed lable, and on it, it will list the countries and the relevant gas categories that apply.
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