Gravimetric dosing

Weight/meter control

GRAMETRO is a continuous loss-in-weight gravimetric dosing unit designed for extruder feeding and supervision, it manages the weight-per-meter ratio of the extruded material in a closed loop. A control algorithm supervises the haul-off speed in combination with the extruder, thereby keeping a constant quantity of extruded material for every linear meter also in multilayer applications.

  • Consistent extrusion feeding
  • Self-adapting
  • Throughput control
  • Quick start-up time
  • Automatic calibration



Continuous loss-in-weight batch dosing unit

GRAMIXO is a gravimetric batch blender with an integrated loss in weight extrusion control, which can be used to manage up to eight components.  It features a removable inclined mixer and easy access openable transparent body panels. The dosing management system is integrated with the extruder screw, haul-off, and continous thickness control.  When used for bubble film applications the cooling ring can also be managed by GRAMIXO to further enhance performance and stability. GRAMIXO has been specifically designed for extrusion applications where gram per meter control is paramount.

  • Multi-component
  • Double eyelid shutter
  • Removable inclined mixer
  • Vibration immunity system
  • Quick Recipe changes


Continuous loss in weight multi-component dosing system

GRAVICO is a continuous loss-in-weight multi-component dosing system equipped with an automatic weight/liner meter adjustment and designed for continuous cycle processing (film, pipes, profiles, mono and co-extruded sheet). This dosing system is designed for use with up to eight components for wide range of configurations.  GRAVICO is automatically managed by the NAVIGATOR 9000 control for automated management of the system production parameters including: cooling ring control, gauge control, extruder haul-off and extruder speed.

  • Multi-component
  • 4,000 weight samplings per second
  • Self-adapting
  • Vibration immunity
  • Throughput control
  • Quick start-up time and changeover


Continuous micro blender

GRAMIKRO is a continuous loss-in-weight and multi-component dosing system designed for precise dosing in extrusion systems requiring regular flow and a constant blend.  All connected components are based on a loss-in-weight principle and the dosing percentages further managed by the NAVIGATOR 9000 control.  GRAMIKRO is compatible with starve feed extruders and features vibration immunity for installation directly on the extruder.

  • Multi-component
  • Starve feeding compatible
  • 4,000 weight samplings per second
  • Self-adapting
  • Vibration immunity
  • Throughput control
  • Quick start-up time and changeover


Conveying systems

EXA is a multi-material, three-phase conveying system capable of managing up to six material receivers, with a smart suction unit and centralized high efficiency filter.  It is based on the “one-wire” concept where a single wire connects all the receivers.  In addition, EXA features a proportional valve for regrind material and a bypass valve to ensure consistent cycle efficiency.  The loading system management is integrated in the dosing system control and creates a single interface for the operator, which can further be accessed via a wireless tablet connection.

  • Bypass valve for improved cycle efficiency
  • Integrated line cleaning valve control
  • Integrated remote contol
  • Expandable to 80 clients (OW3)


Contrex S.r.l.

Via dell'Artigianato 20,
35010 Massanzago (PD) - Italy
Tel. +39 0423 920147
Fax +39 0423 920167
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