Description: The Gas Level Indicator can be used on propane, butane or mixed fuel gas cylinders. The magnetic backing means it can be attached to the outside of the cylinder. The has been mainly designed as a warning device which shows the gas bottle is running out. It is not a precise gauge of how much gas is left in the bottle, which is why the is placed near the bottom of the bottle.
The Science of the On the label, each vertical bar is a different temperature liquid crystal mixture. There are 12 LC bars in total which ensures that whatever the ambient air temperature (where the bottle is stored), there will always be at least one LC bar that is showing colour. When gas is discharged from the cylinder ( i.e being used) the liquid changing to gas inside the bottle causes the cylinder to cool and a noticeable temperature difference is noted on the cylinder’s surface, above and below the liquid level.
The cooling is caused by the gas absorbing heat energy from the cylinder and its surroundings because it changes from liquild ( under perssure) to a gas as it is released. The LC bar is able to indicate the change in temperature by changing colour vertically (blue to green to red) and show where the liquid gas level is. If the LC bar shows a constant colour the gas liquid gas level is above( or below) where the indicator has been placed.
