L.P.G. cylinder.

[David Schweizer]

Sorry, not quite true that, they also gradually accumulate quite a lot of water, that must be added to the tare weight but you don't know how much there is without totally evacuating the gas and re weighing.

<{POST_SNAPBACK}>

I am intrigued. How does a sealed container in which the contents are under pressure, absorb moisture and where does it get it from?

[John Orentas]

Then how do you know you've got the gas you paid for? (rhetorical)

<{POST_SNAPBACK}>

 

That is the point, you don't. Unless you weigh before and after. That is why we have weights and measures inspectors and trading standards chaps, they control it.

[John Orentas]

Every time a bottle is filled with LPG a small and unpredictable amount of water enters the bottle, a by product of the distillation process and difficult to remove I was told. Obviously as the water cannot be burned with the gas it builds up over time and after a lot of re-fillings the company go to some trouble to get it out.

 

In my youth I was partly responsible for commissioning a filling plant at the Calor depot in Grangemouth Scotland.

 

The machine consisted of a massive roundabout which had 20+ sophisticated automatic weighing machines around it's perimeter, bottles passed onto the machines through an escapement. The only operations that needed human intervention was the keying into the system of the 'empty' weight of the bottle indicated by a separate check weigher.

 

The bottles travelled around the "Magic Roundabout" and on their cicuit where automatically filled to a pre-set weight and were ejected onto a conveyor, all fully automatic. As you may imagine this is a very simpified description of this impressive contraption.

 

All you chaps out there who cannot perceive of a world without computer technology may like to consider how this was done with nothing but pneumatic systems. No electrics of any kind could be used for obvious reasons. We where pretty smart in those days.

Edited April 19, 2005 by John Orentas

[dor]

The only operations that needed human intervention was the keying into the system of the 'empty' weight of the bottle indicated by a separate check weigher.

 

So was the tare weight checked each time? If so, only the slight amount of water with the gas would be charged for, as any water building up in the bottom of the cylinder would be included with the tare weight.

 

And I've yet to notice any liquid in th ebottom of a cylinder when it is empty, so how significant is this problem?

[John Orentas]

So was the tare weight checked each time? If so, only the slight amount of water with the gas would be charged for, as any water building up in the bottom of the cylinder would be included with the tare weight.

 

And I've yet to notice any liquid in th ebottom of a cylinder when it is empty, so how significant is this problem?

<{POST_SNAPBACK}>

 

I deliberately used the words "empty weight", in other words the tare weight plus the accumulated water, the weight of water water was not always "slight" it eventually became sufficient to prevent the correct amount of LPG being put in.

 

As with any contained liquids it is important not to totally fill the vessel, expansion room must be allowed.

 

If you give your empty bottle a good shake you will often feel a quantity of liquid swilling about.

Edited April 19, 2005 by John Orentas