Application Variables of Remote Actuated Valves | exida

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Application Variables of Remote Actuated Valves

Remote actuated valve assemblies (RAVA) are a frequently used final element of safety instrumented functions (SIF) in the process industry.  Studies of field failure data at exida has shown potentially dangerous failures of these valve assemblies significantly depend on how they are used – the application.

As a simple example, consider the supply of gas to a storage tank.  A SIF may be designed to address high pressure causing an explosion: a pressure transmitter observes that the pressure exceeds a programmed threshold, an actuator is de-energized by a safety PLC switching a solenoid to vent, a passive element like a spring canister moves the actuator as actuator hold pressure decreases, which closes the valve and stops the inflow of gas into the tank. The action of closing the valve is known as a trip. This configuration is known as “close on trip.”

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