Gravifeed – Gravimentric loss-in-weight continuous blender for starve feed extruders

Continuous gravimetric blender, designed to blend pellets, regrind and flakes in extrusion processes where key-factors are the dosing accuracy, and the capability to follow and compensate the variations of unstable processes.

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Vibratory Tray Feeder.
Each ingredient (mains and additives) is continuously metered by individual vibratory tray feeders.

Therefore the system is suitable to feed pellets and also regrind and flakes, with a wide variety of bulk densitiesì and flowability.

Self-supporting structure prearranged for vacuum receiver installation without additional supports.

The on-board control box does not require any floor space.
Reduced installation costs. Complete wiring of the dosing unit is factory made.

Quick and easy access to all parts for maintenance cleaning.
Clean out doors for fast removal of dust or ingredient residues and for visual inspection.

Drain spout for quick and complete ingredient feed hopper emptying.

Dedicated standard weights kit for load cells calibration.

Extrusion control with starve feeding extruders

Operator inputs the Melt Pressure Set‐Point (PSP) by the HMI
Being the melt pump pressure directly related to the line total throughput (kg/h), Line Control system converts the PSP into a Troughput Set‐Point (TSP) and the TSP is sent, as an input, to the GRAVIFEED
The Line Control system gets the melt Pressure Present‐Value (PPV) from the melt pump
The Line Control system converts PPV) into the relevant Troughput Present‐Value (TPV)
TPV is sent, as an input, to the GRAVIFEED
The GRAVIFEED adjusts the throughput of each component:
– to keep the receipt
– to adjust TPV = TSP and keep therefore PPV= PSP

On the throat of the processing machine
On a mezzanine, to feed by gravity the supply hopper of the processing machine
On a vacuum take-off stand, to feed one or more processing machineas blending station