Shutdown Valve Solenoid Fault Detection Through Venting Correlation
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Solution Overview
Problem
Existing systems fail to detect failures in solenoid valves that de-energize ON/OFF valve actuators independently, which can lead to dangerous undetected faults jeopardizing the safety integrity of Shutdown Valves in Safety Instrumented Systems, as a simple shutdown test cannot distinguish between solenoid valve failures when all systems are activated simultaneously.
Innovation Solution
A detector system comprising sensors to monitor solenoid valve energization and de-energization, fluid venting, and actuator states, with a microcontroller to evaluate correlations and generate real-time fault messages, allowing for wireless transmission and reducing maintenance through failure detection and correlation analysis.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If multiple independent systems (ESD, PSD, DCS) are used to control solenoid valves for SDV actuation, then system reliability and safety integrity are improved, but the ability to detect individual solenoid valve failures is degraded because a simple shutdown test cannot distinguish which solenoid valve failed
Solution Approach 1:
The patent segments the monitoring function by providing individual detectors for each solenoid valve (SOV1, SOV2, SOV3) connected to different control systems (ESD, PSD, DCS). Each detector independently monitors its associated solenoid valve's energization state and fluid venting, allowing identification of which specific valve failed rather than detecting only the general shutdown outcome. This segmentation resolves the contradiction by maintaining the multi-system reliable control architecture while enabling precise failure identification.
2Difficulty of detecting and measuring
If multiple detectors and monitoring systems are added to detect solenoid valve failures, then failure detection capability is improved, but device complexity increases
Solution Approach 1:
The patent employs universal detector units that can be applied to any solenoid valve regardless of which control system (ESD, PSD, or DCS) it belongs to. Each detector performs the same dual function: monitoring energization state and detecting fluid venting. This multi-functionality approach standardizes the detection mechanism across all three control systems, reducing overall system complexity through repetition of a proven, simple detector design rather than creating complex specialized monitoring circuits for each valve.
Solution Approach 2:
The detector system implements feedback by continuously monitoring the solenoid valve's energization state and fluid venting condition, then providing real-time information about the valve's operational status. The detector compares the expected state (based on control system commands) with the actual state (detected through energization monitoring and fluid venting detection), and generates failure signals when discrepancies are detected. This feedback mechanism enables automatic failure identification without adding complex diagnostic logic.
3Reliability
If continuous monitoring of solenoid valve states is implemented, then dangerous undetected faults are reduced, but energy consumption and system resource usage increase
Solution Approach 1:
The detector system maintains continuous monitoring of solenoid valve states through constant detection of energization levels and fluid venting conditions. This continuous action ensures that dangerous undetected faults are immediately identified regardless of when they occur in the operational cycle. The monitoring operates continuously rather than periodically, eliminating detection gaps while the simple detector design keeps energy consumption minimal compared to the value of continuous safety assurance.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
Enhances system availability by accurately identifying solenoid valve failures, reducing testing and maintenance efforts, and ensuring the safe operation of Shutdown Valves by distinguishing between solenoid valve failures, thereby maintaining the safety integrity of the Safety Instrumented System.
Implementation Method 1
at least one solenoid valve (SOV1, SOV2, SOV3) to be electrically controlled by external control systems A, B and C, wherein the solenoid valve assembly unit is characterized by
Implementation Method 2
at least one detector which monitor if a solenoid valve has closed and properly and vented the fluid to de-energize the ON/OFF valve actuator
Data Source
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AI summary
It is disclosed a system and method to detect or determine faults in a valve activation system of an on/off valve (V1) with an actuator (4) connected to a pneumatic or hydraulic pressurized fluid line (7). The system includes at least one solenoid valve (SOV1, SOV2, SOV3) connected in the fluid line (7) ahead of the actuator (4), wherein each connected solenoid valve (SOV1, SOV2, SOV3) is activated by a solenoid (SO1, SO2, SO3) controlled by an external control system (A, B, C), said solenoid valves being adapted to block the fluid line (7) when de-activated, and vent the fluid line (7) releasing the pressure from the actuator (4), which will de-energize the actuator (4) and move the on/off valve (V1) to safe position. The system further includes a current detector (CD12, CD14, CD16) associated with each connected solenoid (SO1, SO2, SO3) monitoring magnetizing current in said solenoid, a fluid flow detector (VENT1, VENT2, VENT3) associated with each connected solenoid valve (SOV1, SOV2, SOV3) detecting any flow of fluid vented from the fluid line (7) through the solenoid valve, and a controller (51) connected to and monitoring signals from each connected current detector (CD12, CD14, CD16) and each connected fluid flow detector (VENT1, VENT2, VENT3).