# Aldi Gas Bottle Level Indicator



## Steve (22/10/07)

Noticed in the latest Aldi junk mail catalogue there was a safety cut off valve type of thing for gas bottles and it had a guage showing gas level in the bottle. Any one got one of these? Im sick of trying to guess how much i have left in the bottle. $24.99 or something like that.
Cheers
Steve


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## NickB (22/10/07)

I've got one of these, grabbed it from BigW a few months back for around the same price I think.

Very handy to have, but have noticed that when you first turn on the gas, you need to give the dial a good push down to get an accurate reading.

Apart from that, $25 well spent I think!

Cheers


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## Screwtop (22/10/07)

Have had one for years, waste of time for monitoring gas level, good as a gas fuse though for safety. Gas stays in the green until about 10 minutes before it runs out. As NickB says remember to push down on the guage after connecting to the bottle.


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## chimera (22/10/07)

sounds exactly the same as the gas fuses from bunnings, right down to the push dial to prime.

Agree with screwtop, the gauge is a vague 'indication', definitely not linear, will sit somewhere in the top 1/4 for the life of the bottle then drop rapidly pretty much as the flames go out on the burners.. bit like the fuel gauge on my first car..


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## Steve (22/10/07)

Chimera said:


> sounds exactly the same as the gas fuses from bunnings, right down to the push dial to prime.
> 
> Agree with screwtop, the gauge is a vague 'indication', definitely not linear, will sit somewhere in the top 1/4 for the life of the bottle then drop rapidly pretty much as the flames go out on the burners.. bit like the fuel gauge on my first car..




no worries - thanks all...you've just saved me some money.


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## chimera (22/10/07)

reckon the best part about the gas fuse is having a laugh at the expense of your mate who's been trying to light it for 10 minutes and declared the main and spare bottle to both be empty

also, it's meant to be a safety device or something


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## chovain (22/10/07)

Screwtop said:


> Have had one for years, waste of time for monitoring gas level, good as a gas fuse though for safety. Gas stays in the green until about 10 minutes before it runs out. As NickB says remember to push down on the guage after connecting to the bottle.



There's a good reason for them being inaccurate: When most gasses are held at high pressure, they have an equilibrium head pressure. That is, they turn into a quantity of nice dense liquid such that the equilibrium pressure is met. As you take gas out, the liquid changes back to a gas to keep that head pressure the same. Only once you run out of liquid does the head pressure start to drop. Once that happens, you are literally running on fumes, and will very soon run out.

The keggers will be used to this concept: The intake gauge on your regulator will stay at ~800kPa (???) for ages. Once it starts to drop, you'll notice that it drops _really_ quickly.

There are better ways of telling how much gas you have left:
* Use a set of bathroom scales, and measure yourself with and without the gas bottle. The bottle should have the empty weight stamped somewhere (or just do a test measurement with an empty cylinder).
* While you are using the gas, use some funky physics. As liquid turns to into a gas (through decompression), it drops in temperature. Because the liquid form is so much denser than the head space gas, it is able to hold more heat, so will feel cooler. Look for a line of condensation, or feel for where the cylinder is cooler - that's where the liquid level is up to.


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## winkle (22/10/07)

These "SmartStrip liquid level indicator" which are sold to show the liquid level in kegs be useful on a LPG bottle? (Damm cheaper if they are.)


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## chovain (22/10/07)

winkle said:


> These "SmartStrip liquid level indicator" which are sold to show the liquid level in kegs be useful on a LPG bottle? (Damm cheaper if they are.)



They work by getting the user to spray them with hot water. The hot water warms the strip. The part of the keg with liquid in it cools the strip faster than the head-space does. That's extremely unlikely to work on an idle gas bottle, as the temperature will drop too slowly, and will tend to fall quite evenly (as heat spreads throughout the strip). It may not even get down to a temperature where the strip activates (it may need to get down below room temperature). 

It would probably work on an active bottle quite well though, as long as the rate of gas consumption is high enough to get the bottle temperature down.


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## Stuster (22/10/07)

I think you'd be better off spending the money on a second gas bottle.


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## Cortez The Killer (22/10/07)

I was gonna say that 


Stuster said:


> I think you'd be better off spending the money on a second gas bottle.


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## chovain (22/10/07)

Stuster said:


> I think you'd be better off spending the money on a second gas bottle.



That option is just _so_ underrated! Lets say for example that you have an accurate way of measuring how much gas you have in your single bottle. What do you do if you only have enough for a 45 minute boil? If you're using a swap service, you're throwing away gas!

With two bottles, you don't need to pay much attention to how much gas you have (as long as you remember to replace the empties ), and you don't waste gas if you're a swapper.


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## Stuster (22/10/07)

Mark Chovain said:


> as long as you remember to replace the empties )



So far so good, but I can certainly see that happening to me at some point.


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