Product category:
Control Valves (Rotary, Mixing, Temperature Control etc)
News Release from: Smith Flow Control | Subject: Stroke-Test
Edited by the Engineeringtalk Editorial
Team on 16 April 2004
Tester cuts plant downtime at a stroke
The new Stroke-Test from Smith Flow Control is a novel device that allows testing of critical valves 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
This article was originally published on Engineeringtalk on 20 Apr 2000 at 8.00am (UK)
Related stories
Innovative safety solution for valve change-over
Process safety specialist Smith Flow Control has designed an innovative interlocking system for the change-over sequence between relief valves.
Key-exchange interlocks for safe actuated valves
Whenever valves are actuated by means of pneumatic, hydraulic or electrical power sources, safety specialist Smith Flow Control (SFC) can supply custom-designed key-exchange interlocks.
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 preset 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.
As 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. Request a free brochure from Smith Flow Control ...
• Smith Flow Control: contact details and other news
• Email this article to a colleague
• Register for the free Engineeringtalk email newsletter
• Engineeringtalk Home Page
Search the Pro-Talk network of sites
