Gravimetric Loss-in-Weight Feeder for Precision Powder Dosing

Gravimetric Loss-in-Weight Feeder

The loss-in-weight feeder is the gold standard for precision dosing of bulk materials. It continuously weighs the entire feeder plus its contents, measuring the weight loss over time to calculate the actual feed rate. A PID controller adjusts the feeder speed to maintain the target rate within ±0.25% accuracy.

Operating Principle

The hopper, feeder (screw, vibratory, or belt), and material are all mounted on load cells. As material discharges, the controller calculates the instantaneous feed rate from the weight loss rate. If the actual rate deviates from the setpoint, the controller adjusts the feeder speed proportionally.

Applications

• Cement additive dosing (fly ash, slag, gypsum, limestone)
• Chemical powder metering for water treatment
• Food ingredient batching (flour, sugar, spices)
• Pharmaceutical excipient dosing

Specifications

• Feed rate: 1-200 tph depending on model
• Accuracy: ±0.25% of setpoint (gravimetric mode)
• Hopper capacity: 0.5-20 m³
• Output signals: 4-20mA, Modbus, Profibus