Servo Level Measurement
Continuous liquid level measurement in custody transfer and inventory control applications.
Extended 
Xpert 
Lean 
Xpert 
Xpert Servo Level Measurement
Servo level (servo tank gauging) uses a servo motor to position a small displacer suspended on a measuring wire; when the displacer contacts the liquid, buoyancy changes the apparent weight/torque, which the instrument measures to determine level with very high precision. This technology is used for liquid level, interface, and density in tank gauging applications and is closely associated with inventory management, loss control, and custody transfer requirements.
The benefit is metrology-grade performance. Servo gauges deliver extremely fine resolution and strong repeatability, and the measurement is not dependent on conductivity or dielectric constant. For terminals and refineries, that combination supports accurate stock accounting and reduces uncertainty in high-value product movements.
Engineering considerations include mechanical integration (still pipes, roof nozzles, wire travel path), product cleanliness, and maintenance planning for moving components. Designers also align the instrument selection with applicable standards/approvals, required measurement functions (level vs. interface vs. density), and the tank’s expected operating envelope (temperature, pressure, vapor space conditions).
Typical applications include crude oil, gasoline, diesel, petrochemicals, and chemical storage in tank farms, terminals, and refinery operations. Servo gauges are commonly applied where custody transfer-quality measurement is needed, and where the plant’s tank gauging system aggregates level, temperature, and other parameters for reconciliation and reporting.
Operationally, servo instruments are usually part of an integrated tank gauging architecture, feeding inventory software, terminal automation, and reconciliation tools. Effective use includes defined calibration/verification routines, condition monitoring for wire/displacer health, and well-structured alarm strategies to protect against overfill while preserving measurement integrity.
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