Due to the flowable nature of liquid products, you can pump the material to several different possible entry points.
You can dose into a blender if any premixing is necessary; you can dose directly into the throat through an adapter tube that can bring your dosing within 0.5 inches [1.27cm] of the screw; or you even have the ability to dose downline on the barrel of the extruder either through a vent hold or a manually drilled hold depending on desired location.
With the Riverdale Gravimetric System (RGS) and Pump In A Drum (PIAD) technology, dosing is simple. Only electrical power and an air supply is needed to run the RGS dosing units. No calibration is required – an operator simply enters the let-down ratio of the liquid material, the throughput of the extruder (in lbs/h or kg/h), and the density of the liquid material (which can be found on the label of the pail/drum). The RGS also has the ability to run in continuous or extrusion following mode (where dosing is determined by the speed of the screw).
Optimal applications for liquids include production of pre-colored compounds and incorporation of highly concentrated additives at low let-down ratios.