For practical reasons, professionals sometimes need to transfer gas from a large cylinder to a smaller container to be used as a work site gas cylinder. This allows welders and other users to avoid carrying a bottle that is too heavy. The safety measures are drastic, as the danger of explosion is very real. Here’s what you need to know.
The dangers of LPG, propane and butane gas
Butane and propane gases are hydrocarbons in gaseous form that are liquefied to be packaged in a gas cylinder for multiple uses. They are particularly flammable and, when mixed with air, the slightest spark can cause an explosion. Of course you should not smoke, but you should not use a mobile phone near your work site either. LPG (liquefied petroleum gas) is also sensitive to temperature changes and expands when the temperature rises.
This is why you must carry out all your manipulations outdoors, in the absence of any spark or flame, and always have a fire extinguisher handy. You must use protective gloves and goggles, as the evaporation of the gas can cause burns.
How to fill your bottle with an Express Filling Connector
Propane or butane gas should only be transferred from a 13 kg net weight cylinder. You should never fill your construction cylinder completely, to allow for expansion when the temperature rises. If you have inadvertently overfilled it, open the tap in the open air to drain off the excess.
Your gas cylinder of 13 kilos net must be fixed upside down. This can be done using a specially designed stand or by attaching the bottle to a sufficiently sturdy wall bracket. The bottle must be perfectly stable. The one you wish to fill is placed next to it, on the floor, head up.
Never connect the two cylinders directly, but use a decanter fitting with a gasket at each end. Tighten the nuts firmly by hand. You must check that your installation is perfectly watertight by spraying a soapy mixture. Check the valves, the handwheel and the outlet of each cylinder.
Start by opening the valve on the small work cylinder first, then slowly open the valve on the large cylinder. The work bottle will fill slowly and you should hear the sound of the decanting. Be careful not to open the valve on the large cylinder too quickly, otherwise there is a risk of underfilling. If necessary, close it and then open it again more slowly.
Then unscrew the drain from the small bottle with a screwdriver. You can see a little gas escaping through the threads. When the cylinder is full, the gas starts to form droplets. Then screw the drain back in with your screwdriver, without forcing.
In case of flow control valve
Your gas cylinder may be equipped with a flow restrictor. Check by removing the safety plug : This is the case if the gas flow is almost immediately slowed down when you open the valve. In this case, you have to open your 13 kg bottle very little, i.e. only a quarter or an eighth of a turn. Filling will only be a little slower.
When finished, close the cylinder valves and remove the decanting connection.
The total weight of the full cylinder should never exceed 5.7 kg. Otherwise you must vent the excess gas, always outdoors and away from any flame or spark.