gas bottle half full or half empty who knows????
- Thread starter dazicki
- Start date
hehehe theres always one
no serious we had a gadget to check it but it was rubbish i thought maybe there was an easy way like if i weighed them would that work?????
no serious we had a gadget to check it but it was rubbish i thought maybe there was an easy way like if i weighed them would that work?????
nope
just pick up the bottle and tip it from side to side you can feel the gas inside sloshing about no slosh no gas its as simple as that with practice you can be quite accurate at guessing whats left
but the best thing is if you can carry the weight: is to carry a spare always full then you will never run out
hands up all thoughs who have run out of gas after tea on sunday when you cannot get any more????
oh just me then?
colin
just pick up the bottle and tip it from side to side you can feel the gas inside sloshing about no slosh no gas its as simple as that with practice you can be quite accurate at guessing whats left
but the best thing is if you can carry the weight: is to carry a spare always full then you will never run out
hands up all thoughs who have run out of gas after tea on sunday when you cannot get any more????
oh just me then?
colin
I've had the BP light gas bottle fitted to the new van, mainly to help reduce nose weight. You can also see the level of the gas through the fibreglass cylinder so no more guess work,
Gavin.
Gavin.
http://www.care-avan.co.uk/gasangel.shtml[/quote
Hi Klarkey,
Have you tried one of these as I am very intrested on how accurate they are as I am limited to one propane 6 kg and a camping gaz 907 to keep nose weight down and a lot of time in France
Thanks Rob
Hello Dazicki
The most accurate method of assessing how much gas is in the bottle is by weight. That is how they do when they are filled so - there's some maths involved but here's how;
Assuming you are using Calor or one of the other main supplies in the UK, each of the bottles will have a TARE WEIGHT stamped on the bottle. This is the weight of the empty bottle. So disconnect all regulator and pipe work , weigh your unknown bottle, and subtract the TARE WEIGHT and what you have left is the weight of the LPG left in the bottle.
There are other methods, which can give an indication,
Some ultrasonically measure the depth of the liquefied gas in the bottle using a transducer under the bottle.
Some use a liquid crystal temperature sensitive strip which is attached to the side of the bottle. As the temperature changes the LCD changes colour. This uses the fact that as you use gas, the temperature of the Liqufied gas drops compared to the gas vapour, so there is a temperature change at the surface of the liquid, which is detected and displayed as a colour change on the strip.
This only works when gas is being used, so bottles that have bee standing for a long time do not show this temperature change.
None are as accurate as by weight.
The most accurate method of assessing how much gas is in the bottle is by weight. That is how they do when they are filled so - there's some maths involved but here's how;
Assuming you are using Calor or one of the other main supplies in the UK, each of the bottles will have a TARE WEIGHT stamped on the bottle. This is the weight of the empty bottle. So disconnect all regulator and pipe work , weigh your unknown bottle, and subtract the TARE WEIGHT and what you have left is the weight of the LPG left in the bottle.
There are other methods, which can give an indication,
Some ultrasonically measure the depth of the liquefied gas in the bottle using a transducer under the bottle.
Some use a liquid crystal temperature sensitive strip which is attached to the side of the bottle. As the temperature changes the LCD changes colour. This uses the fact that as you use gas, the temperature of the Liqufied gas drops compared to the gas vapour, so there is a temperature change at the surface of the liquid, which is detected and displayed as a colour change on the strip.
This only works when gas is being used, so bottles that have bee standing for a long time do not show this temperature change.
None are as accurate as by weight.
I seem to remember something about pouring boiling water on the bottle which causes it to frost at the level of the gas.
unfortunately iv'e not got one of these,van is fitted with automatic gas level gadget(bottle sits on contraption which measures weight of bottle).works by weight which gives a digital reading on a small screen how much gas is in the bottle,seems to work ok
Hello Dazicki
The most accurate method of assessing how much gas is in the bottle is by weight. That is how they do when they are filled so - there's some maths involved but here's how;
Assuming you are using Calor or one of the other main supplies in the UK, each of the bottles will have a TARE WEIGHT stamped on the bottle. This is the weight of the empty bottle. So disconnect all regulator and pipe work , weigh your unknown bottle, and subtract the TARE WEIGHT and what you have left is the weight of the LPG left in the bottle.
There are other methods, which can give an indication,
Some ultrasonically measure the depth of the liquefied gas in the bottle using a transducer under the bottle.
Some use a liquid crystal temperature sensitive strip which is attached to the side of the bottle. As the temperature changes the LCD changes colour. This uses the fact that as you use gas, the temperature of the Liqufied gas drops compared to the gas vapour, so there is a temperature change at the surface of the liquid, which is detected and displayed as a colour change on the strip.
This only works when gas is being used, so bottles that have bee standing for a long time do not show this temperature change.
None are as accurate as by weight.
The most accurate method of assessing how much gas is in the bottle is by weight. That is how they do when they are filled so - there's some maths involved but here's how;
Assuming you are using Calor or one of the other main supplies in the UK, each of the bottles will have a TARE WEIGHT stamped on the bottle. This is the weight of the empty bottle. So disconnect all regulator and pipe work , weigh your unknown bottle, and subtract the TARE WEIGHT and what you have left is the weight of the LPG left in the bottle.
There are other methods, which can give an indication,
Some ultrasonically measure the depth of the liquefied gas in the bottle using a transducer under the bottle.
Some use a liquid crystal temperature sensitive strip which is attached to the side of the bottle. As the temperature changes the LCD changes colour. This uses the fact that as you use gas, the temperature of the Liqufied gas drops compared to the gas vapour, so there is a temperature change at the surface of the liquid, which is detected and displayed as a colour change on the strip.
This only works when gas is being used, so bottles that have bee standing for a long time do not show this temperature change.
None are as accurate as by weight.
Hello Brian,
Perhaps you are thinking of the frost you sometimes see on Propane bottles where a lot of gas is being used, such a roofing contractors.
Here the gas being drawn off the bottle has to be replaced by vaporising the liquefied gas at the bottom of the bottle. As the liquid vaporises it uses heat from its surroundings to give the molecules enough energy to jump out of the liquid to form the vapour above it. This cools the body of liquid, and because Propane can do this down as low as minus 40C, the outside of the bottle is cold enough to cause water vapour from the atmosphere not only to condense on the outside of the bottle, but to cool it enough to freeze it at the level of the liquid in the bottle.
The same thing tries to happen with Butane, but Butane only vaporises operates down to about zero C, so the bottle rarely gets cold enough to actually freeze water, but it can be cool enough to cause waster vapour to condense below the liquid level. The LCD strip mentioned above uses the same temperature differential process to display the liquid level.
You can use hot water to get a Butane bottle to produce gas when the weather is about freezing point, but the water wont freeze because of the bottle.
Perhaps you are thinking of the frost you sometimes see on Propane bottles where a lot of gas is being used, such a roofing contractors.
Here the gas being drawn off the bottle has to be replaced by vaporising the liquefied gas at the bottom of the bottle. As the liquid vaporises it uses heat from its surroundings to give the molecules enough energy to jump out of the liquid to form the vapour above it. This cools the body of liquid, and because Propane can do this down as low as minus 40C, the outside of the bottle is cold enough to cause water vapour from the atmosphere not only to condense on the outside of the bottle, but to cool it enough to freeze it at the level of the liquid in the bottle.
The same thing tries to happen with Butane, but Butane only vaporises operates down to about zero C, so the bottle rarely gets cold enough to actually freeze water, but it can be cool enough to cause waster vapour to condense below the liquid level. The LCD strip mentioned above uses the same temperature differential process to display the liquid level.
You can use hot water to get a Butane bottle to produce gas when the weather is about freezing point, but the water wont freeze because of the bottle.
I work in a hospital and the oxygen bottles (large size) sometimes come with two gauges, one to show how much pressure is in the bottle (approx how full the bottle is) and another showing the regulated pressure out.
I am suprised nobody had developed something similar, maybe it would just be too expensive.
I am suprised nobody had developed something similar, maybe it would just be too expensive.
I've seen a propane regulator with a pressure gauge somewhere. The problem is, like the LPG gauge in my Jeep which works on pressure, they're about as accurate as firing a dart out your a***.
Colin Yorkshire, both hands well and trully up in the air
ran out of gas in France 5 days before comming home last year
( what a plonker) also last year same holiday no water in van, tap bust on day 2 of holiday.
Still had a grate time though.
Wont run out of gas this year
Kevin H
ran out of gas in France 5 days before comming home last year
( what a plonker) also last year same holiday no water in van, tap bust on day 2 of holiday.
Still had a grate time though.
Wont run out of gas this year
Kevin H
thanks kevinH I dont feel so bad now
ok guys gadgets I like but dazicki asked whats is the beat way
to tell if your bottle needs a refill ie before it runs out because we dont replace it with gas in do we? well I dont anyway but then I learned my lesson and carry a spare
I agree the only true method is by weight but that does not tell you how long it will last unless of course you weigh it every day
like I said the slosh method does work and can be very accurate with practice but do it before the shop closes
ok guys gadgets I like but dazicki asked whats is the beat way
to tell if your bottle needs a refill ie before it runs out because we dont replace it with gas in do we? well I dont anyway but then I learned my lesson and carry a spare
I agree the only true method is by weight but that does not tell you how long it will last unless of course you weigh it every day
like I said the slosh method does work and can be very accurate with practice but do it before the shop closes
Hi John L , definately remember reading about the boiling water test somewhere. I'm off on Wednesday so will give it a try ;O)
Meanwhile found these on net..
"Pour a jug of boiling water down the side of the bottle then slowly run your hand up from the base of the bottle. You will notice a change in temperature at some point ie hotter this is the approx level of the liquid inside"
Yes, this test works. I use it regularly when I'm in the field. It relies on water evaporating faster above the level of the "gas" in the bottle than below it. Think about kinetic energy, states of matter, mass above and below a liquid/gas interface, conduction, convection and heat-conducting metal containers.
1. Pour boiling water down container from top to bottom.
2. Watch the water evaporate faster above the "gas" level in the bottle.
Note 1: Tap-temperature "cold" water can be substituted.
Note 2: It is often possible to feel the temperature difference with your finger if you use cold water.
Cheers
Michael -*I've done the experiment*- V
Ok ,might have got the frosting bit wrong but worth a try .
Brian (",)
Meanwhile found these on net..
"Pour a jug of boiling water down the side of the bottle then slowly run your hand up from the base of the bottle. You will notice a change in temperature at some point ie hotter this is the approx level of the liquid inside"
Yes, this test works. I use it regularly when I'm in the field. It relies on water evaporating faster above the level of the "gas" in the bottle than below it. Think about kinetic energy, states of matter, mass above and below a liquid/gas interface, conduction, convection and heat-conducting metal containers.
1. Pour boiling water down container from top to bottom.
2. Watch the water evaporate faster above the "gas" level in the bottle.
Note 1: Tap-temperature "cold" water can be substituted.
Note 2: It is often possible to feel the temperature difference with your finger if you use cold water.
Cheers
Michael -*I've done the experiment*- V
Ok ,might have got the frosting bit wrong but worth a try .
Brian (",)
Hello Rubix,
Surprise surprise, I used to work in a hospital many years ago, and also had to review the condition of O2 cylinders.
The O2 stored in hospital cylinders is just compressed gas. So as it is used the pressure drops is in proportion to the volume of gas used.
Butane and propane is also stored under pressure, but significantly as you increase the pressure of either Butane or Propane the gas reaches a triple point at which the gas spontaneously changes from a vapour to a liquid. And this state occurs within normal room temperatures.
The same can happen to O2 but it has to be subject to much greater pressure and kept well below freezing point, (I think it is -198C) which is not safe option inside hospitals.
The LPG bottle contains both liquid and vapour, and when you use some gas, the liquid actually boils to release more vapour to equalise the pressure. So whilst there is any liquid left in the bottle, the pressure in the bottle will remain quite stable (subject to the temperature of the bottle) and only when all the liquid is vaporised, will the pressure begin to follow the characteristic of the hospital O2 bottle, but by then your virtually out of gas anyway.
There are some of the older regulator change over systems that do incorporate a bottle pressure gauge, but their value is primarily to show when a bottle has finished rather than how much gas is left.
Surprise surprise, I used to work in a hospital many years ago, and also had to review the condition of O2 cylinders.
The O2 stored in hospital cylinders is just compressed gas. So as it is used the pressure drops is in proportion to the volume of gas used.
Butane and propane is also stored under pressure, but significantly as you increase the pressure of either Butane or Propane the gas reaches a triple point at which the gas spontaneously changes from a vapour to a liquid. And this state occurs within normal room temperatures.
The same can happen to O2 but it has to be subject to much greater pressure and kept well below freezing point, (I think it is -198C) which is not safe option inside hospitals.
The LPG bottle contains both liquid and vapour, and when you use some gas, the liquid actually boils to release more vapour to equalise the pressure. So whilst there is any liquid left in the bottle, the pressure in the bottle will remain quite stable (subject to the temperature of the bottle) and only when all the liquid is vaporised, will the pressure begin to follow the characteristic of the hospital O2 bottle, but by then your virtually out of gas anyway.
There are some of the older regulator change over systems that do incorporate a bottle pressure gauge, but their value is primarily to show when a bottle has finished rather than how much gas is left.
Hello Brian,
Yes I can see how that might work, though I would not rely on it as a measure of how much gas may be remaining. It is only an indicator and quite a crude one.
The only accurate way is by weight.
However looking at Daziki's question the only time a gas bottle needs a refill is when its empty!
Yes I can see how that might work, though I would not rely on it as a measure of how much gas may be remaining. It is only an indicator and quite a crude one.
The only accurate way is by weight.
However looking at Daziki's question the only time a gas bottle needs a refill is when its empty!
thanks you lot a few good ideas im gonna try the weight one first and hopefully it will give me an idea,we hardly use our gas maybe for half an hour at tea time,we dont have an oven,we use a halogen heater and electric fridge and always hahave a one ring camping stove with us so we should be ok
something that i was told by the gas supplier we use is puzzling me though
is it true that if i run out of gas in cornwall when i go to a camping shop they wont just swap the bottle for a full one and that id have to buy a new bottle which would then be different colour from the ones up here(lancs)and that then my local gas supplier wont just swap it for a full one and id have to buy another new one
is he just winding me up???
something that i was told by the gas supplier we use is puzzling me though
is it true that if i run out of gas in cornwall when i go to a camping shop they wont just swap the bottle for a full one and that id have to buy a new bottle which would then be different colour from the ones up here(lancs)and that then my local gas supplier wont just swap it for a full one and id have to buy another new one
is he just winding me up???
Hello again Dazicki
You may already know that most LPG stockists are franchised to a particular supplier. Calor gas is a trade name and is available at their stockists across the country, a similar situation occurs for Shell Gas, but there are many other suppliers who only operate in smaller areas.
Generally you only rent the bottle from the supplier, so they expect it to be returned to them. That is fine for national companies such as Calor, and Shell but if you rent your bottle from a local supplier in your area, they probably won't have any exchange arrangements in other parts of the country, and that seems to be what your supplier is telling you.
Now - from what you write about your gas usage, it seems to me that it is actually quite low, and one small bottle will probably last you quite a long time, so if you start out with as full bottle it will probably last you a week of light usage.
For safety you could take a spare bottle, but perhaps rent it from a national supplier, then, regardless of where you go, you can at least get it exchanged locally if you need to.
You may already know that most LPG stockists are franchised to a particular supplier. Calor gas is a trade name and is available at their stockists across the country, a similar situation occurs for Shell Gas, but there are many other suppliers who only operate in smaller areas.
Generally you only rent the bottle from the supplier, so they expect it to be returned to them. That is fine for national companies such as Calor, and Shell but if you rent your bottle from a local supplier in your area, they probably won't have any exchange arrangements in other parts of the country, and that seems to be what your supplier is telling you.
Now - from what you write about your gas usage, it seems to me that it is actually quite low, and one small bottle will probably last you quite a long time, so if you start out with as full bottle it will probably last you a week of light usage.
For safety you could take a spare bottle, but perhaps rent it from a national supplier, then, regardless of where you go, you can at least get it exchanged locally if you need to.
Hi Rubrix,
Good idea, but the dual head pressure gauges (one for bottle pressure and one for supply pressure) only work when the bottle contains pressurised gas.
The Oxygen gas bottle you see at work contains gas at (say) 2000 psi when full, and this pressure drops as gas is drawn off - and is a very good indicator of capacity.
This won't work on a caravan LPG bottle, because these contain liquid and gas under pressure - and as gas is drawn off by an appliance, liquid boils to replace the lost gas - and the bottle pressure doesn't change.
And for this same reason, the gas gauges don't work (very well) either - the pressure remains the same until very close to being empty - and they only start moving as the bottle runs out.
Robert
Good idea, but the dual head pressure gauges (one for bottle pressure and one for supply pressure) only work when the bottle contains pressurised gas.
The Oxygen gas bottle you see at work contains gas at (say) 2000 psi when full, and this pressure drops as gas is drawn off - and is a very good indicator of capacity.
This won't work on a caravan LPG bottle, because these contain liquid and gas under pressure - and as gas is drawn off by an appliance, liquid boils to replace the lost gas - and the bottle pressure doesn't change.
And for this same reason, the gas gauges don't work (very well) either - the pressure remains the same until very close to being empty - and they only start moving as the bottle runs out.
Robert
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