The Stroke-Test from Smith Flow Control is a device that allows testing of critical valves without shutting down the process flow. This ensures the revenue stream is not interrupted, while also ensuring plant operators comply with industry safety standards.
The system operates on the principle of valve partial stroke testing, which allows a safety system to close a valve only partially. So, when a Stroke-Test is fitted to a valve, it limits the movement of the actuator to within pre-set travel limits, for example 20°. This means that all the valve control elements, such as solenoids, positioners and relays are tested, without the valve having to fully close.
Since the valve is only partially closed during the test, the flow coefficient is not significantly affected and process flow continues. If the valve is inoperable due to a mechanical failure, misalignment, or some other control anomaly, it will be detected during the partial stroke test.