aultymer Posted October 30, 2011 Share Posted October 30, 2011 I always have a chuckle when the penny pinchers say, "I wouldn't recomend this to anyone who is not competent but I know what I am doing" (or words to that effect) then go on to describe inverting the donor bottle to aid the flow of gas!!! P1 x V1 = P2 x P2, the effect of gravity may be disregarded for this equation. Link to comment Share on other sites More sharing options...
derek pringle Posted October 30, 2011 Share Posted October 30, 2011 Hi, Some short cuts and some savings are in my opinion just not worth the risk. If people want to refill or self fill gas bottlles I think they should have a bona fide system installed. Gaslow I know is not cheap but it does do what it says on the tin and you do not have to go 'out of the way ' to fill the cylinders as someone has indicated. It is a safe and proven system. keep safe cheers derek Link to comment Share on other sites More sharing options...
Brambles Posted October 30, 2011 Share Posted October 30, 2011 aultymer - 2011-10-30 10:10 AM I always have a chuckle when the penny pinchers say, "I wouldn't recomend this to anyone who is not competent but I know what I am doing" (or words to that effect) then go on to describe inverting the donor bottle to aid the flow of gas!!! P1 x V1 = P2 x P2, the effect of gravity may be disregarded for this equation. It would help if you got the equation correct!! It is not just about the gravity increasing the flow, it is about inverting the bottle so liquid gas can exit the outlet and transfer to the refillable bottle. Incidently gravity is everything if the two bottle are at the same temperature, the only thing which will make the LPG transfer is gravity. The transfer is extremely slow in this case because the upper bottle will cool as the gas empties and the lower bottle will warm up. As the temperature of the bottles stabilise to ambient the pressures will equalise as the gas converts back to liquid. This leaves only gravity as the only external influence on the transfer system to allow the transfer to complete over time. We can influence the transfer by warming the higher bottle and cooling the lower, but gravity is still a very significant factor along with the height between the upper bottle and lower. Link to comment Share on other sites More sharing options...
Mel B Posted October 30, 2011 Share Posted October 30, 2011 Ian03/54 - 2011-10-29 8:28 PM Mel B - 2011-10-29 7:14 PM What you seem to forget though is that every time you exchange a cylinder for a refilled one, the refilled one has been fully tested before it was filled by the supplier, | Can you produce a link showing this to be the case, please? Or do you mean that the cylinder has a date stamped proving it's useful life? Thanks. From memory, I believe it was an article in the MMM magazine, possibly this year, which covered what happens to Calor bottles when they are returned to be refilled, so it isn't a 'guess', it is, as far as I can recall from the article what happens, whether it happens EVERY time it is refilled I can't say as I don't work there it appears to be a maximum of 6 refills before it is thoroughly tested from what I've found on the web. If someone can remember the actual month it was in the mag I'll have a shuftie as I have them going back quite a few years. :D I haven't had a Calor bottle for a while as I have a Gaslow system, but I don't recall them having a 'useful life' date on them, if a bottle develops a fault/is damaged etc, it would be picked up during the testing which is carried out prior to it being refilled. Link to comment Share on other sites More sharing options...
aultymer Posted October 30, 2011 Share Posted October 30, 2011 So sorry - had finger trouble this morning so my post should have read :- P1 x V1 =P2 x V2 ! This does not change no matter whether you invert, or raise or lower respective containers. The entire process is driven by pressure not gravity. Heat applied to the donor cylinder will raise the pressure by causing the gas to expand, ie , increasing P1 and will speed transfer until equilibrium is reached. I have no problems with financially challenged or plain mean people doing this, just don't ask others to do it. Ps, any spelling mistakes do not change the laws of the universe!! Link to comment Share on other sites More sharing options...
Guest peter Posted October 30, 2011 Share Posted October 30, 2011 Ian03/54 - 2011-10-29 8:28 PM Mel B - 2011-10-29 7:14 PM What you seem to forget though is that every time you exchange a cylinder for a refilled one, the refilled one has been fully tested before it was filled by the supplier, | Can you produce a link showing this to be the case, please? Or do you mean that the cylinder has a date stamped proving it's useful life? Thanks.Of course she can't. I've got a 1200 Ltr bulk tank in my front garden and it never gets tested before re-filling. The guy just plugs in the filler and opens a bleed valve to allow the gas to get in the tank and watches the tank guage to see when it's 80% full and shuts off the valve. When the filler nozzle is disconnected quite a bit of gas is released and is dispered into atmosphere, so long as there is no spark or flame it's not a problem. Link to comment Share on other sites More sharing options...
Guest peter Posted October 30, 2011 Share Posted October 30, 2011 aultymer - 2011-10-30 8:38 PM So sorry - had finger trouble this morning so my post should have read :- P1 x V1 =P2 x V2 ! This does not change no matter whether you invert, or raise or lower respective containers. The entire process is driven by pressure not gravity. Heat applied to the donor cylinder will raise the pressure by causing the gas to expand, ie , increasing P1 and will speed transfer until equilibrium is reached. I have no problems with financially challenged or plain mean people doing this, just don't ask others to do it. Ps, any spelling mistakes do not change the laws of the universe!!Just who is asking anybody to do anything. It's obviously something you're not interested in doing, so why do you have to come on this thread and try and convince everybody that it's either inherently dangerous or only poor or tightfisted people would consider it?. As it mainly concerns filling only Camping Gaz cylinders which are a rip off to buy re-filled, it is of no concern of people with Gaslow or any other system of re-filling onboard cylinders. So why come onto the thread bleeting about safety?. I just can't understand the self righteous attitude of some folk on here. That think only their view is valid and anyone having a different one is either poor a fool. or tightfisted. As I have said earlier in this thread all the safety issues have already been gone over many times in the link provided and do not need to be repeated in this thread ad nauseum. Link to comment Share on other sites More sharing options...
Ian0354 Posted October 30, 2011 Share Posted October 30, 2011 Mel B - 2011-10-30 7:51 PM Ian03/54 - 2011-10-29 8:28 PM Mel B - 2011-10-29 7:14 PM What you seem to forget though is that every time you exchange a cylinder for a refilled one, the refilled one has been fully tested before it was filled by the supplier, | Can you produce a link showing this to be the case, please? Or do you mean that the cylinder has a date stamped proving it's useful life? Thanks. From memory, I believe it was an article in the MMM magazine, possibly this year, which covered what happens to Calor bottles when they are returned to be refilled, so it isn't a 'guess', it is, as far as I can recall from the article what happens, whether it happens EVERY time it is refilled I can't say as I don't work there it appears to be a maximum of 6 refills before it is thoroughly tested from what I've found on the web. If someone can remember the actual month it was in the mag I'll have a shuftie as I have them going back quite a few years. :D I haven't had a Calor bottle for a while as I have a Gaslow system, but I don't recall them having a 'useful life' date on them, if a bottle develops a fault/is damaged etc, it would be picked up during the testing which is carried out prior to it being refilled. Thank you for the further explanation. I'll have to search my back copies as I don't recall reading that article. I asked because I have seen the way that empty gas bottles are thrown around, risking very real damage, at the local dealer and would be reassured to know they were tested. As I understand every Calor bottle is stamped with the date of manufacture so that Calor know when to withdraw it from use. Regards, Link to comment Share on other sites More sharing options...
aultymer Posted October 30, 2011 Share Posted October 30, 2011 Peter "So why come onto the thread bleeting about safety?. " I don't know where you got the idea that I was bleating about safety! I was only pointing out the physics behind the transfer of gasses. Tell us all - does your tanker driver park on top of your bulk tank to re-fill it? This is a forum where people come to explore ideas with other like minded people. Your postings appear to contain an element of bullying. Link to comment Share on other sites More sharing options...
Guest 1footinthegrave Posted October 30, 2011 Share Posted October 30, 2011 I think anyone who has got a van that only takes a 904 or 907 cyclinders has frankly got the wrong van. The danger that information like this is available at the click of your mouse is that complete idiots may try it and get into all sorts of trouble, and after all some folk need protecting from themselves, Rod Hull would have been much better off leaving it to the professionals for example. Link to comment Share on other sites More sharing options...
Guest peter Posted October 30, 2011 Share Posted October 30, 2011 aultymer - 2011-10-30 10:08 PM Peter "So why come onto the thread bleeting about safety?. " I don't know where you got the idea that I was bleating about safety! I was only pointing out the physics behind the transfer of gasses. Tell us all - does your tanker driver park on top of your bulk tank to re-fill it? This is a forum where people come to explore ideas with other like minded people. Your postings appear to contain an element of bullying. Did you not post this.... "I have no problems with financially challenged or plain mean people doing this, just don't ask others to do it." Does that not imply that you are concerned about the safety of the process?. The tanker driver does not park on top of my tank, he parks next to it, but the tank on the truck is higher than mine so makes no difference. Also the gas is pumped in. Show me where my postings contain an element of bullying. I don't care if anybody or nobody fills their own cylinders. You posted above "This is a forum where people come to explore ideas with other like minded people" Which by definition means, you only want to correspond with people that think the same as you and are not interested in any other peoples views. Now.....that to my mind is bullying. Link to comment Share on other sites More sharing options...
Guest peter Posted October 30, 2011 Share Posted October 30, 2011 1footinthegrave - 2011-10-30 10:50 PM I think anyone who has got a van that only takes a 904 or 907 cyclinders has frankly got the wrong van. The danger that information like this is available at the click of your mouse is that complete idiots may try it and get into all sorts of trouble, and after all some folk need protecting from themselves, Rod Hull would have been much better off leaving it to the professionals for example.you don't get it do you? The 907 is used for my barbecue, as Ive already pointed out. Do you really think that anybody with a coachbuilt van would choose to use 907 cylinders. Link to comment Share on other sites More sharing options...
Brambles Posted October 30, 2011 Share Posted October 30, 2011 Aultymer, P1x V1 = P2 x V2. You are implying here the pressure varies depending on the volume. This is not true. The pressure is fixed irrespective of volume and depends on temperature for a liquified gas occupying an enclosure with a vapour phase. Therefore if you have two bottles, one nearly empty and one nearly full, both at the same temperature, then the pressure will be the same for both. If there are different temperatures affecting the pressure then LPG transfer will take place, but is still totally irrespective of volume. This is actually over simplifying it as the are other factors to take into account regarding the vapour phase pressures, but certainly your formula is totally irrelavent in this application. Hence you should see now why raising supply bottle higher than the other means gravity does have a significant effect , because the weight of the LPG in the upper bottle will cause transfer to the lower bottle. The upper bottle will cool so will absorb heat slowly from the ambient, the lower bottle will warm up giving up heat to the ambient and so eventually the transfer occurs, as a result of gravity. I am trying to keep this as simple as possible, because there are actually some other factors involved. Jon. Link to comment Share on other sites More sharing options...
Guest 1footinthegrave Posted October 30, 2011 Share Posted October 30, 2011 PETER As it happens I do, can't recall the exact model but it was an autosleeper, bloke was complaining about being limited to 907's. Look mate you do as you like with your barbecue, and I must have missed that you were specifically referring to filling your barby bottle in the OP. I took it as a dummies guide to diy re-filling, and there's lots of them about. Read one of my posts about the guy with the ( still) leaking underslung gas tanks intending to board a ferry, a dummy if ever I've met one ! Anyway whatever...................... Link to comment Share on other sites More sharing options...
aultymer Posted October 30, 2011 Share Posted October 30, 2011 "The guy just plugs in the filler and opens a bleed valve to allow the gas to get in the tank and watches the tank guage to see when it's 80% full and shuts off the valve." OR "Also the gas is pumped in. " Which one of your stories is true , Peter? "You posted above "This is a forum where people come to explore ideas with other like minded people" Which by definition means, you only want to correspond with people that think the same as you and are not interested in any other peoples views. Now.....that to my mind is bullying." I don't think many people will recognise your definition of my post but just in case there is any misunderstanding - You are wrong. Link to comment Share on other sites More sharing options...
Guest 1footinthegrave Posted October 31, 2011 Share Posted October 31, 2011 To be fair to the bloke he posted it as his experiences with DIY re-filling, and qualified it with saying he was just sharing the information, not encouraging anyone to do it. My problem with that is some ****head will try it and put himself and possibly others in harms way, IMO better to keep some things to yourself. Link to comment Share on other sites More sharing options...
Brambles Posted October 31, 2011 Share Posted October 31, 2011 Not talking about this is not going to stop people doing it, clearly a few on this forum do carry out the practice. I am certainly not going to encourage anyone to try it for the 1st time, far from it as it is potentially extremely dangerous. However, should we not be discussing what the REAL safety issues are and potentially what can go wrong. This way, anyone who does it and continues to do it may learn something. The responsible route is not to hide away from what goes on but to discuss openly without people constantly saying, its dangerous without backing up exactly why. Is it not just as dangerous, or even more so, to refill you gas lighter for your stove with a ligher refill canister in doors or even in your Motorhome, and yet this is a fairly common practice. Could it be argued filling refillable tanks from an LPG pump is more dangerous then transferring gas to a 907 cylinder with proper adapters and high pressure hoses which are secured and bolted tight compared to a push on coupling used Joe Public which could be damaged by the previous user or getting worn out. What about the guy filling his petrol tank and is not paying attention and gets spillage of petrol on the forecourt. I recall one car, cannot remember which model or make, which was recalled to have an alteration made to the petrol fill pipe. Apparently the action of filling could cause static and a spark...OOPS, that sounded quite a serious recall. I mention this, beause maybe this is something which should be considered refilling bottles via high pressure rubber hoses, is there a possibility of static build up in the lower container, and when the pipe is unscrewed a spark could occur. So a safer option would now be to use a braided hose to transfer LPG so static is dicharged and both cylinders remain at the same potential. So my safety tip is to make sure both bottles are connected together and grounded for safety. Is it a problem? I do not know, but certainly grounding the bottles eliminates any question of it being an issue and the question of is it a problem no longer exists. edit - some links which may be interesting to read as in some sections it highlights the sort of issues which can be overlooked by the professional suppliers and be dangeous regarding use of tanks etc. Think I have the right links http://www.hse.gov.uk/foi/internalops/hid/din/545.pdf http://www.hse.gov.uk/foi/internalops/hid/din/546.pdf http://www.propane101.com/propanecylinderexplosions.htm Link to comment Share on other sites More sharing options...
Derek Uzzell Posted October 31, 2011 Share Posted October 31, 2011 I may well still have the Calor-related magazine article Mel B refers to, but (if I can't find it) I'm pretty sure that the normal procedure for refilling a Calor bottle would not involve any 'testing' as such unless the bottle itself was considered to require refurbishment. That's when the bottle would be steam-cleaned internally, pressure/leak-tested, repainted, etc. but, otherwise, the bottle would just be visually inspected and refilled. As far as decanting LPG in liquid form from one bottle to another is concerned, surely exploiting gravity to carry out that process is the only practicable method for the 'amateur' refiller? Basically, one bottle is connected to another, with the 'donor' bottle inverted and positioned higher than the 'recipient' bottle. Gravity then causes the liquid LPG to transfer from the former bottle to the latter and the process will normally be slow as the bottle outlets and connecting hose/pipe will be narrow diameter. That gravity causes the transfer to take place is easily realised by envisaging a (notional) system where both bottles had, say, 100mm-diameter outlets connected by a 100m-diameter hose. Then the gravity-fed transfer-rate would be very fast indeed. Seems obvious to me... Link to comment Share on other sites More sharing options...
Brambles Posted October 31, 2011 Share Posted October 31, 2011 Wish we did not have onbly 30 mins to edit a post.. Would like to change my above post extensively. 1. do not want to sound lieke I ensorsig refilling. 2. I have not emphasised enough how dangerous the practice of refilling can be in the wrong hands. One thing you must always expect, and this applied to forecourt refilling as well, is a malfunction and a gas bottle might not shut off, it could be ice formming, dirt, or seal failure. So always be prepared for a bottle to empty itself. So free open space well away from buildings or combustable materials is a must. Always turn the supply bottle back upright before removing any adapters. It is not uncommon for push on type automatic valves on the cylinder to leak ( appllies to propane taps as well) and have seen liquid gas shoot out from an inverted bottle. Fortunately Butane evaporating cools very quickly and stays liquified, but propane is another story. There is also a risk if say it sprays on you you get severe frost damage. This equally applies to LPG forecourts and refilling if you get a liquid leak so always wear thick NON ABSORBANT protective gloves and thick clothing. Refilling in a T shirt is not recommended. Those who refill will think I am being over reactive, I am not....accidents do happen and you need to protect against accidents, and be prepared for any eventuality as well as having a fire extinguisher to hand. Do peope still feel inclined to refill? I hope not, but if you must then make it safe and the above is only a small fraction of what should be considered in my view. I a not trying to put people off who want to carry on refilling, but like me, I want to be aware of any risks I have overlooked. ( I don't think I am making much sense am I??? Kind of trying to be careful what I write and influenced by knowing this is quite a tabboo subject for many). Will I read my two posts in a week and think what a numptie and rediculous posts -- probbaly! Link to comment Share on other sites More sharing options...
Brambles Posted October 31, 2011 Share Posted October 31, 2011 Derek, your post makes sense to me. One of the issues is the clip on butane connectors, they are not designed for high flow rates of gas let alone liquid so this is a limiting factor in the transfer rate. Link to comment Share on other sites More sharing options...
Guest Peter James Posted October 31, 2011 Share Posted October 31, 2011 I use item 16643 http://www.bes.co.uk/products/063.asp camping gaz adaptor, and find the 907 cylinder fills with propane to safe capacity in about 8 minutes. I use a 907 cylinders with a single ring in the top because Ibelieve its safer in a vehicle than a cooker with pipes that could leak. Although Camping Gaz works out about 4 times the price of Calor, and I don't like being taken for a mug, it is not just about saving money. Its easier for me to refill a 907 cylinder from my Calor cylinder, than it s to carry it down to the camping shop for an exchange cylinder. Yes I still have to take the Calor cylinder in for exchange, but less often as it holds 7 times as much. And I can get it from a garage forecourt that doesn't do camping gaz. But when I go abroad I have no worries about running out of gas because camping gaz is available throughout Europe, unlike Calor etc. Link to comment Share on other sites More sharing options...
Mel B Posted October 31, 2011 Share Posted October 31, 2011 peter - 2011-10-30 9:11 PM Ian03/54 - 2011-10-29 8:28 PM Mel B - 2011-10-29 7:14 PM What you seem to forget though is that every time you exchange a cylinder for a refilled one, the refilled one has been fully tested before it was filled by the supplier, | Can you produce a link showing this to be the case, please? Or do you mean that the cylinder has a date stamped proving it's useful life? Thanks.Of course she can't. Gee-wiz Peter, thanks for that, why don't you just call me a liar! 8-) I KNOW I read an article on it, and assumed it was in the MMM mag, but maybe it was in the Caravan Club mag or one of the others I've read ... I shall make a point of finding it just for you!!!! :-> Link to comment Share on other sites More sharing options...
Derek Uzzell Posted October 31, 2011 Share Posted October 31, 2011 Mel B - 2011-10-31 6:18 PM Gee-wiz Peter, thanks for that, why don't you just call me a liar! 8-) I KNOW I read an article on it, and assumed it was in the MMM mag, but maybe it was in the Caravan Club mag or one of the others I've read ... I shall make a point of finding it just for you!!!! :-> I suspect that the article you read was "CALOR Gas Cylinders" by John Wickersham, published in the February 2003 Caravan Club Magazine (pages 40-41). This article describes the work carried out at Calor's Saxham refurbishing plant, but makes no claim that every Calor cylinder is given special treatment before every refill. (If you want a copy, PM me with an e-mail address and I'll send you a scanned version.) Link to comment Share on other sites More sharing options...
Guest peter Posted October 31, 2011 Share Posted October 31, 2011 aultymer - 2011-10-30 11:57 PM "The guy just plugs in the filler and opens a bleed valve to allow the gas to get in the tank and watches the tank guage to see when it's 80% full and shuts off the valve." OR "Also the gas is pumped in. " Which one of your stories is true , Peter? "You posted above "This is a forum where people come to explore ideas with other like minded people" Which by definition means, you only want to correspond with people that think the same as you and are not interested in any other peoples views. Now.....that to my mind is bullying." I don't think many people will recognise your definition of my post but just in case there is any misunderstanding - You are wrong. This man is >>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>> Link to comment Share on other sites More sharing options...
aultymer Posted October 31, 2011 Share Posted October 31, 2011 Great answer Peter. Link to comment Share on other sites More sharing options...
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