These fume skirts are air operated devices actuated when the lances starts to enter the container. They are designed to recover 99% of the fumes from the container being filled and help prevent splashback at the bung opening during the fill cycle.

The bellows are lowered by an air cylinder and covers the bung opening creating a positive seal. The controller adjusts for the weight at the automatic tare. Fumes are extracted out of the side exhaust port.