A Standard Sensor Turns Into Something Entirely New

A large Permian Basin operator operates numerous hydraulically and pneumatically actuated dump valves in its onshore field operations with a valve position monitoring system. These valves open and close frequently to unload vessels and redirect flow to other parts of the process.

While the pneumatic controls operated the valves reliably, engineers lacked detailed visibility into how often the valves were cycling and whether they were functioning properly. In some cases, valves would remain partially open, maintaining a small flow position that can accelerate wear and reduce valve life.

Our solution was a custom-designed monitoring system with a stationary horizontal sensing bar and a movable half-moon “puck” mounted to the valve stem. Within is a small embedded magnet, while the sensing bar houses a high-resolution, three-axis magnetometer. As the valve stem moves up and down, the magnet’s field changes, allowing precise detection of valve position.

In our lab, we calibrated the system by cycling a representative valve through its full range of motion, creating a detailed curve of magnetic field strength versus valve position. The electronics are highly accurate, providing position measurements within 1% of full scale.

The system captures data at high frequency (every five seconds instead of the usual one-minute interval) and transmits summarized data to the server every 15 minutes.

This solution gives the operator a new level of insight into valve performance and operating patterns. It provides early detection of abnormal behavior, reduces maintenance costs, and provides data that was previously unavailable through conventional instrumentation.