Stroke-Test valves on critical safety duties

Eliminate plant downtime at a stroke, by testing critical valves on automated emergency shutdown or other critical points, without shutting down the process flow

The new Stroke-Test from Smith Flow Control is a novel 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 Stroke-Test solves the perennial Catch-22 situation: to maximise revenue, operators are under pressure to keep plant running 24 hours a day, seven days a week, for as many months or years as possible without interruption.

To do this safely, it is necessary to periodically test all automated emergency shutdown or other critical valves.

Testing the valves normally requires them to be shut down, stopping the process flow, and therefore stopping the revenue stream.

The Stroke-Test eliminates this problem by allowing plant operators to do both.

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 degrees.

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.

The main benefit of the Stroke-Test is its simplicity: because it is a wholly mechanical device, it does not need to be integrated into the control loop, as would be necessary with an electrical system.

Because it is mechanical, the device is also much more economical to install and operate than an electrical or controls-driven system.

Finally, the Stroke-Test is built for the most demanding industrial environments: it is vibration-resistant, corrosion protected and independently certified to IP67 to prevent water ingress.

Stainless steel trim is used for all keys, shafts and sockets, and it is permanently lubricated, sealed and requires no routine maintenance.

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