Digital Technology: A Remedy for Sick Shutdown Valves in Safety Instrumented System Applications

Keywords: Safety Instrumented System, Valve Testing, Partial Stroke, Full Stroke, Digital Valve Controller, Signature Test

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Abstract:

In the event of a safety demand, the final control element of a safety instrumented function (SIF) loop is a key component to a process going to a safe state. Unlike the logic solver or sensors (analog transmitters), the final control element requires a total shutdown to check the mechanical integrity. With the invention of the digital valve controller, a final control element’s mechanical movement can be tested online by moving a span of 10% or 15% without disrupting the process. This small test provides considerable improvement in the reliability of the SIF loop. The diagnostics capability of the digital valve controller also reports the health of the valve, thus reducing the need for scheduled maintenance and increasing process availability. The purpose of this paper is to review user concerns and demonstrate the use of digital valve controllers to improve reliability and availability of safety systems while reducing costs. © 2009 Inside Publishing. All Rights Reserved.

Volume: 2009   Issue: 2
EUR 5.04
(Pages: 8, Words: 3360)

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