Increased Breakout Torque
In this example, the failure mode we will examine is an increased breakout torque requirement — a fairly common problem in valves that have been in service for a long time. The valve is behaving correctly up to point A where the actuator’s mechanical slack is taken-up. After this point, the black curve
shows continued exponential decay indicating that there is no movement of the valve or actuator. This continues until point B, where the spring force is finally sufficient to move the valve from its seat and it now moves normally.
As with many other faults, the SVM system can monitor the degrading performance and assist in predicting when the valve should be serviced.