Liquid Volumetric Filling 1. Piston Volumetric Filling A piston filler (Figure 20.4) measures and delivers the product to the container by the action of a single piston for each filler head. Empty Filling Figure 20.4 Piston volumetric filling with rotary valveLiquid Volumetric Filling 1. Piston Volumetric Filling A piston filler (Figure 20.4) measures and delivers the product to the container by the action of a single piston for each filler head. Empty Filling Figure 20.4 Piston volumetric filling with rotary valve