Gravimetric Feeders

High Accuracy Loss in Weight Feeding for Continuous Processes

VOLDE Gravimetric Feeders are engineered for accurate and repeatable mass-flow control of powders, granules and pellets in continuous production processes. Based on the Loss in Weight (LIW) principle, the complete feeder—including the material hopper and feeding mechanism—is continuously weighed to determine the actual material flow in kg/h. Unlike volumetric feeding, which controls material delivery through feeder displacement and speed, gravimetric feeding continuously measures the actual mass being delivered to the process. The control system compares this measured flow with the required setpoint and automatically adjusts the feeder output to maintain the target feed rate. This closed-loop mass-flow control makes LIW feeding particularly suitable for applications where formulation accuracy, process stability and consistent product quality are critical.

| Loss in Weight Feeding Principle

During operation, the feeder continuously measures the reduction in system weight over time and calculates the actual mass flow rate. The controller compares this value with the required setpoint and dynamically adjusts the feeding element to compensate for variations in material behavior and bulk density.

The result is a controlled mass flow that is based on actual material consumption rather than feeder speed alone.

• Continuous mass-flow measurement in kg/h
• Closed-loop gravimetric feed rate control
• Automatic adjustment of feeder speed
• Compensation for variations in bulk density and material flow
• Stable feeding across the defined operating range
• Real-time monitoring of feed rate and total consumption
• Integration with PLC, SCADA and plant control systems

| Continuous Weighing & Dynamic Control

Accurate loss-in-weight feeding depends on more than load cell resolution alone. The complete weighing system, mechanical isolation, feeder configuration and control strategy must work together to provide a stable and reliable weight signal.

FEEDGRAM LIW Feeders continuously evaluate weight loss over time and regulate the feeding device accordingly. Signal processing and control functions minimize the influence of mechanical disturbances and provide stable mass-flow control even at demanding feed rates.

• High-resolution load cell weighing
• Continuous weight-loss calculation
• Dynamic feed rate correction
• Signal filtering for stable weight measurement
• Automatic tare and calibration functions
• Feed rate and consumption trending
• Alarm and deviation monitoring
• Recipe and setpoint management

| Loss-in-Weight Feeder Configurations

_ Single-Screw LIW Feeder

Designed for accurate continuous feeding of free-flowing powders, granules and other bulk materials. Screw geometry and operating range are selected according to material characteristics and required feed rate.

_ Twin-Screw LIW Feeder

Designed for cohesive, poor-flowing and difficult-to-feed powders where improved material engagement and more uniform discharge are required.

_ LIW Spiral Feeder

A shaftless feeding configuration for selected cohesive or difficult materials where an open feeding geometry can help reduce material build-up and improve material flow.

_ LIW Belt Feeder

Provides gravimetric feeding with gentle material handling for free-flowing, fragile or shear-sensitive granules, pellets and other bulk materials where product integrity is important.

| Synchronized Multi-Feeder Control

In continuous formulation processes, multiple FEEDWELL LIW Feeders can operate as a synchronized dosing system. Each feeder independently controls the mass flow of its assigned ingredient while the overall production rate determines the required feed ratio.

When production capacity changes, individual feeder setpoints can be adjusted proportionally to maintain the defined formulation throughout the process.

• Independent mass-flow control for each ingredient
• Master production rate control
• Automatic recipe-ratio calculation
• Synchronized acceleration and deceleration
• Continuous formulation control
• Centralized PLC and SCADA monitoring
• MES and ERP integration options