Derek Uzzell Posted July 14, 2011 Share Posted July 14, 2011 1footinthegrave - 2011-07-14 6:41 AM I can't see that anyone has ridiculed anyone on this thread ( makes a change though ) but all of our experiences of various ways of trying to do this have been reflected here both by me and other posters. In short with perhaps the exception of transparent bottles there appears to be no simple, or completely foolproof way of monitoring how much gas is left in a bottle. Even weighing really tells you nothing other than it's getting lighter or unless you get out a slide rule, I mean who knows how much gas will be given off by say half a Kg left Even mechanical gauges can malfunction as well, although not mechanical my Calor lite bottle gauges have often shown "empty" with another few days usage left. :-( Unfortunately, there are no "transparent bottles", although there are 'translucent' LPG containers (BP Gas Light, Safefill, etc.) This isn't being pedantic - the difference is significant. I have a 5kg Kompozit-Praha cylinder purchased years ago from MTH Gas Systems. It's LPG12 on the following webpage http://kompozitpraha.com/products.htm As LPG is colourless, establishing how much liquid gas remains in my bottle isn't straightforward. With the bottle in the gas-locker and in normal daylight, it's a waste of time trying to spot where in the bottle the gas stops and where the air above it begins. I wait until it's getting dark and then shine a powerful torch through the side of the bottle. This makes it easy to see the 'join' between gas and air most of the time. The exception is when the amount of LPG in the bottle is pretty low, when (as will be evident from the webpage picture) the bottle's outer plastic shell masks the lower part of the inner composite gas-vessel. As my bottle has no 80% cut-off valve, it's important that I accurately ascertain how much gas remains inside so that I know how much LPG can be safely put in at the refilling stage. As pressure-sensitive gauges (like the Gaslow product) won't provide accurate readings of gas-bottle contents across a useful range, as far as I'm aware ALL in-built gas-bottle gauges use a mechanical float-based linkage. Gaslow, Alugas, Calor-Lite, and Stako containers - they all have a mechanical system operating their contents gauges. That such gauges vary in accuracy will be down to the engineering and quality of the mechanical system, but it's easy to understand that, if you have a simple swinging-arm float arrangement in a long slim container, it won't be possible to provide readings across a full range of contents levels. The operation (and limitations) of the Gaslow float-based system are described in the company's brochure http://www.gaslow.co.uk/pdf/Gaslow-2011-brochure.pdf and it will be apparent from the drawings that graduated contents readings will only be available across a range of 50% to 18% full. The gauge system used for the Calor-Lite bottle closely resembles that of the Gaslow cylinders (I've seen the Calor and the Gaslow float systems and had their operation demonstrated to me), so there's no reason to expect greater accuracy, or a greater range, from the Calor product. I vaguely remember seeing a Stako gauge system inside a cut-away bottle, but (other than recalling that it was far better engineered than Gaslow's equivalent) have no memory of the technical details. It's plain that, if you have a gauge that can't register below 18% bottle capacity (as Gaslow state for their own in-built gauge), this means that - for a 21 litre-capacity Gaslow bottle, say - you'd have 3.78 litres of gas remaining when the gauge ceases registering. In my own case, that would mean about 3 days more use on average before the bottle approached genuinely empty, but some motorcaravanners could last for weeks on that quantity of LPG. Link to comment Share on other sites More sharing options...
aultymer Posted July 14, 2011 Share Posted July 14, 2011 Hi Derek, if you are going to be picky about the difference between transparent and translucent you may have to look at your statement about seeing where the 'air and LPG' meet in a bottle! If their is any air in the bottle you may have problems. There should be gas and LPG. What you see is the boundary between the liquid bit and the gas which has boiled off ready to pass to your appliance. Link to comment Share on other sites More sharing options...
Guest 1footinthegrave Posted July 14, 2011 Share Posted July 14, 2011 Transparent - Translucent....... Blimey I'll have to be more careful in my description, but I'm sure most got my drift, sorry to those that didn't. You can see something in the bottle, a bit like a disposable gas cigarette lighter :-S Link to comment Share on other sites More sharing options...
Tony Jones Posted July 14, 2011 Share Posted July 14, 2011 Sorry, double-clicked! Link to comment Share on other sites More sharing options...
Tony Jones Posted July 14, 2011 Share Posted July 14, 2011 We only have room for one Gaslow in "Roxie," and we don't trust the gauge either! But since (unlike exchange bottles) you never waste anything by filling up too early, we just top up as the opportunity arises. In practice, we find it lasts a good week (with daily showers and cooking, OFF hook-up). So after about four days we start keeping an eye out for an LPG station. However, I've squeezed in a tiny Campingaz 901 (and adaptor) as an emergency backup, but in over 3 years only used it once. Just as well, because CG in a 901 is about the most expensive fuel on the planet (barring the stuff they used to put in space shuttles, which ain't usually on the planet)! Link to comment Share on other sites More sharing options...
lizken Posted July 14, 2011 Share Posted July 14, 2011 Complete waste of time and money. If no room for a second bottle, invest in lightweight Calor 6kg propane with a gauge on the bottle Link to comment Share on other sites More sharing options...
Derek Uzzell Posted July 15, 2011 Share Posted July 15, 2011 aultymer - 2011-07-14 10:56 AM Hi Derek, if you are going to be picky about the difference between transparent and translucent you may have to look at your statement about seeing where the 'air and LPG' meet in a bottle! If their is any air in the bottle you may have problems. There should be gas and LPG. What you see is the boundary between the liquid bit and the gas which has boiled off ready to pass to your appliance. Fair comment - mea culpa. Link to comment Share on other sites More sharing options...
Guest 1footinthegrave Posted July 15, 2011 Share Posted July 15, 2011 lizken - 2011-07-14 7:39 PM Complete waste of time and money. If no room for a second bottle, invest in lightweight Calor 6kg propane with a gauge on the bottle I agree with the above with this caveat, I have two Calor lites, but even these are far from the answer if you can only carry one, the one I'm currently using has been showing "empty" for about the last five days usage. From memory I think the Calor instruction on the bottle label is "when showing empty it may soon be time to change the bottle" or words to that affect, so not an exact science and you may well end up exchanging long before the bottle is exhausted if you take the gauge showing empty as gospel,so there you go. (?) Link to comment Share on other sites More sharing options...
lennyhb Posted July 15, 2011 Share Posted July 15, 2011 Read the OP guys, Mike has a re-fillable Gaslow bottle. Link to comment Share on other sites More sharing options...
crinklystarfish Posted July 15, 2011 Share Posted July 15, 2011 Derek Uzzell - 2011-07-15 7:24 AMaultymer - 2011-07-14 10:56 AMHi Derek, if you are going to be picky about the difference between transparent and translucent you may have to look at your statement about seeing where the 'air and LPG' meet in a bottle!If their is any air in the bottle you may have problems.There should be gas and LPG. What you see is the boundary between the liquid bit and the gas which has boiled off ready to pass to your appliance.Fair comment - mea culpa. Apologies for going gratuitously off topic but that as we kind of veered into pedantry, that quoted Derek was a Dereck. I know I'm onto something, I just don't know what it is. Oh, and Stako with a float guage: as good as it gets. And to be really reliable, fit an 'old style' 37Mbar regulator direct to the cylinder rather than one of the stupid auto-gooing compromise 30Mbar pigtail jobbies that have been ill-advisedly thrust upon us. Gaslow shmazlo. Link to comment Share on other sites More sharing options...
Guest 1footinthegrave Posted July 15, 2011 Share Posted July 15, 2011 lennyhb - 2011-07-15 10:10 AM Read the OP guys, Mike has a re-fillable Gaslow bottle. Dyslexia is my excuse, but the fact remains stick on gauges, useless, Gaslow, just fill it up even if you know it's not empty based on the gauge being inaccurate, simple, as they say. :$ Link to comment Share on other sites More sharing options...
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