The operating principle of a piston doser:
The piston doser sucks pneumatically via a ball valve the liquid in and forces the liquid through a second ball valve in an empty container. The conversion of different container sizes works quickly and easily. About a spindle is adjusted with a digital counter of the intake path and thus the adjusted amount to be filled. Thus, the containers can be changed from 0.1 to 1.25 liters without major remodeling.
With one of the great advantages of a piston metering is that it requires no pump in the flow, as he sucks the product itself constantly.