Safety Valve Verification Using Sensor-Guided Partial-Stroke Tests
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Solution Overview
Problem
Current methods for checking the functionality of safety valves, such as partial stroke tests, have limitations including restricted stroke length and starting conditions, which can lead to incomplete assessments and potential disruptions to ongoing operations, necessitating periodic full stroke tests despite the operational state of the system.
Innovation Solution
A method involving a first and second partial stroke test, where the second test is conducted with a larger stroke range, dynamically adjusted based on sensor data to minimize disruption, allowing for more comprehensive evaluation of safety valve functionality without interrupting normal operations.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a full-stroke test is performed to fully demonstrate the functionality of a safety valve, then the reliability of the safety valve is improved, but the productivity of the system is worsened due to interruption of ongoing operation
Solution Approach 1:
The full-stroke test is segmented into multiple partial-stroke tests with different stroke lengths. The method divides the verification process into a first partial-stroke test with a smaller stroke and a second partial-stroke test with a larger stroke, allowing comprehensive functionality assessment without requiring a complete system shutdown.
Solution Approach 2:
Instead of performing a complete full-stroke test that would fully disrupt operation, the method applies partial action through multiple partial-stroke tests. The second partial-stroke test uses a larger stroke than the first, providing more thorough verification while still maintaining system operation, thus avoiding the need for complete interruption.
2Productivity
If a partial stroke test is performed during operation to avoid interrupting work processes, then the productivity is improved, but the reliability of the assessment is worsened due to restricted stroke length
Solution Approach 1:
The assessment is segmented into two stages: a first partial-stroke test with limited stroke to minimize disruption, followed by a second partial-stroke test with larger stroke to enhance reliability. This segmentation allows the system to balance operational continuity with comprehensive functionality verification.
Solution Approach 2:
The first partial-stroke test serves as a preliminary action that prepares the system for the second, more comprehensive test. By initially performing a smaller stroke test, the system can assess basic functionality and then proceed to a larger stroke test that provides more reliable verification without requiring full system interruption.
3Reliability
If the second partial-stroke test is performed with a larger stroke range to provide more comprehensive evaluation, then the reliability of assessment is improved, but the disruption to ongoing operations increases
Solution Approach 1:
The method dynamically adjusts the stroke length based on system conditions. The second partial-stroke test uses a larger stroke than the first, but the exact stroke length can be adapted to current operational parameters, allowing comprehensive assessment while minimizing disruption to the extent permitted by the process state.
Solution Approach 2:
The method changes the stroke parameter between the first and second partial-stroke tests. The second test uses a larger stroke parameter to improve assessment reliability, while the system monitors process conditions to ensure the disruption remains within acceptable limits defined by the method.
Data Source
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AI summary
A method is proposed for verifying the functionality of a safety valve (310) with a valve element and a positioner (340) for controlling the position of the valve element. The safety valve (310) is part of a system in which a process involving a process medium takes place. The system includes a sensor (350) for monitoring the condition or a property of the system and/or the process and/or the process medium. Based on a measured value from the sensor (350), a time point during the ongoing operation of the system is determined at which the functionality of the valve (310) can be tested as part of a partial stroke test. The test can also be monitored using the sensor (350), and the stroke range traversed during the test can be dynamically adjusted to the condition or property. The test can thus be carried out safely during operation and, moreover, with an optimized stroke range.The procedure allows for more frequent testing and more reliable statements about the functionality of the safety valve (310).