EH52ARH said:
Hi Prof, I was thinking more along the line of, when a person pulls up at an lpg. Pump do the staff , see the bottle or do you just connect and fill. And then pay. If so it sounds a bit "cowboy" system to me.
How each company operates is fundamentally down to their own training and procedures, I was trained to refill portable cylinders in an industrial context, We had about 10 Cylinders which were used at various points around our site for a range of purposes. and we filled them from a bulk tank with pressure pump.
We had to check the cylinders for damage, and were not time expired (for pressure testing), Record the serial number its stated tare weight and its measured tare weight. If there was a difference it meant the cylinder was not completely empty. We could only fill it by weight, and it must not exceed its stated capacity added to its tare weight.
A slight problem can be each time the bottle is refilled with commercial grade LPGs., the new gas will have some contaminants which will gradually build up inside the cylinder. In reality this isn't going to be very much, pergaps a few grammes, but it is important that these contaminants are periodically washed out, which is one of the things Calor and other rental firms do this with their bottles.
Periodically our cylinders had to be sent away to our bottle supplier to be completely emptied and hydraulically pressure tested. They were returned with new valve gear and a collar stating the next due date for testing.
That was our system, but others may exist. Commercially gas is sold by weight, so if there are a build up of contaminants, customer s will not be getting their correct measure of LPG. So there is weights and Measures element to there are approved codes of practice for the refilling process, but it is up to the business involved to devise their own management systems.