A Servo Tank Gauge (STG) is a highly precise instrument used for continuous level measurement in storage tanks containing liquids such as crude oil, chemicals, LNG, and refined petroleum products. The accurate positioning of the gauge in the liquid medium is critical for ensuring high-precision inventory control, custody transfer, and safety monitoring.
How Servo Tank Gauges Ensure Accurate Positioning
Servo Motor Control System
The gauge uses a servo-driven displacer suspended in the liquid.
The servo system continuously adjusts the displacer’s position to maintain equilibrium.
Displacer-Based Measurement
The displacer is partially or fully submerged, and the buoyant force changes based on liquid level.
The system precisely detects these changes to determine the exact level.
Automatic Density Compensation
By measuring the displacer’s buoyancy, the STG can calculate liquid density in real time.
This ensures accurate compensation for varying product densities.
High-Resolution Feedback Mechanism
Equipped with high-resolution encoders, the gauge detects even the smallest changes in level.
Measurement accuracy is typically ±0.4 mm or better, depending on the model.
Integration with Tank Gauging Systems
Servo gauges integrate with inventory management software for real-time monitoring.
Compatible with temperature and pressure sensors to correct for environmental factors.
Advantages of Accurately Positioned Servo Tank Gauges
✅ Highly Accurate Liquid Level Measurement – Essential for custody transfer and stock reconciliation.
✅ Real-Time Density and Interface Measurement – Useful for multiphase liquids (e.g., oil-water interface detection).
✅ Minimal Maintenance & Long-Term Stability – Reliable operation with automated self-checking.
✅ Safe for Hazardous Environments – Explosion-proof and ATEX-certified options available.