Gain-in-Weight (GIW) and Loss-in-Weight (LIW) Volumetric and Gravimetric Feeder

GEA provides a wide range of volumetric and gravimetric powder feeding systems to guarantee high accuracy dispensing for critical applications.

There are many types of feeders available to handle bulk solids and they can be divided into two categories: volumetric and gravimetric. A volumetric feeder discharges a volume of material as a function of time while a gravimetric feeder weighs material.


  • Dosing systems 
  • Minor/major ingredient preparation systems 
  • Pre-mix systems 
  • Recipe handling systems 
  • Blending systems 
  • Packing systems

Additional options for mixing, stirring, spreading and pulse elimination, and for handling difficult materials with special properties (sticky, stringy, lumpy, aerated, cohesive, abrasive, dusty or fragile) are also available.

Specialized systems that do not use screws, such as vibratory feeders, rotary valve feeders, belt feeders and others can also be supplied.


Volumetric Feeders

Volumetric feeding systems use an auger or screw conveyor running at a constant speed to discharge powder from a storage hopper at a consistent rate (volume per unit time such as L/min). Frequently, the hopper includes devices to condition the bulk material to ensure an even bulk density by using vibration, agitation, massaging or other means to eliminate air pockets and maintain flow.

A wide variety of screw designs is available from GEA to suit your specific application, including:

  • single or twin screw 
  • half pitch or double pitch flights 
  • open flight helix and side/top discharge nozzles 
  • polyethylene helix 
  • variable pitch helix.

Gravimetric - Loss in Weight

Gravimetric feeding systems generally use a volumetric feeder associated with a weighing system to control the discharge of powder from a storage hopper at a constant weight per unit time (kg/min). The weight signal is used as a feedback control system to constantly monitor the feed rate and compensate for variations in bulk density, porosity etc.

Weighing systems may include platform scales, load-cells, weigh hoppers and other devices to provide optimum performance as required by design requirements. System design may be based on Loss-in-Weight or Gain-in-Weight principles depending on the overall process requirements.