6. Filling

Filling drums with built-in plungers uses the principle of phase imbalance filling, a variant of isobarometric filling, which does not fully respect the equality of pressures between the gaseous phase in the filler's tank and that in the container being filled. The aim is to accelerate filling speed, which is limited by the small fluid flow cross-sections installed in the plungers.

This will require a filling stop mechanism that is no longer provided hydrostatically by a system for detecting the end of filling, which will then be achieved by a valve with pneumatic or electric actuator, and the use of different means for determining the end of filling (ranging from a mini water hammer, recorded when the liquid reaches the level of the gas return tube, to a float-type drain valve, to electrode detection, or even flowmetered filling.