Liquid Filling Machines can come equipped with diving head nozzles that allow the fill head to enter the container prior to actually filling the container. 

The overflow filler from Liquid Packaging Solutions features diving heads that seal onto the container opening and allow product to "overflow" and recirculate for the next filling cycle.

Other filling machines, such as graivity fillers and pump fillers, may incorporate diving heads to avoid splashes and spills from foam or to permit bottom up filling of containers.