Isolation Valve Switchover Manifold for Online Partial Stroke Testing
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Solution Overview
Problem
Conventional emergency isolation valve (ZV) systems require full shutdown for testing, while smart-type systems can perform partial stroke tests online, but are prone to unintended closures due to smart valve positioner failures, disrupting process operations.
Innovation Solution
A switchover kit that couples an air supply to a solenoid valve and smart valve positioner, allowing the ESD controller to switch between direct and positioner-mediated air flow paths, enabling partial stroke testing without interrupting operations and maintaining safety by bypassing the smart valve positioner during normal operations.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If smart valve positioner is used to enable partial stroke testing, then testing capability is improved, but reliability deteriorates due to unintended closures
Solution Approach 1:
The air supply system is segmented into two independent paths: one through the smart valve positioner for testing, and one direct path for normal operation. This segmentation allows the system to isolate the smart valve positioner's influence during normal operations, preventing unintended closures while preserving testing capability when needed.
Solution Approach 2:
A manual isolation valve is introduced as an intermediary component between the air supply and solenoid valve. This intermediary allows operators to selectively route air flow, enabling the system to bypass the smart valve positioner during normal operations while allowing its use during testing, thus resolving the reliability issue while maintaining testing capability.
2Reliability
If full shutdown is performed for testing, then reliability is improved, but productivity deteriorates
Solution Approach 1:
The system transitions from a static testing mode (requiring full shutdown) to a dynamic mode where the testing configuration can be changed online. The manual isolation valve enables the system to dynamically switch between conventional and smart-type operations, allowing testing to be performed during normal operations without interrupting the process.
Solution Approach 2:
The manual isolation valve is pre-configured in the conventional operation position during normal operations. When testing is required, the valve position is changed in advance to enable smart-type operation, allowing partial stroke testing to be performed online without requiring full shutdown of the process.
3Extent of automation
If smart valve positioner is always connected, then automation is improved, but device complexity increases due to failure modes
Solution Approach 1:
The smart valve positioner is extracted from the mandatory operational path and placed in an optional testing path. The manual isolation valve allows the smart valve positioner to be completely disconnected from the air supply during normal operations, eliminating its potential to cause unintended closures while preserving its automatic operation capability when needed for testing.
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
Enables online switching between conventional and smart-type operations, preventing unintended ZV closures and allowing maintenance during operation, thus ensuring continuous and safe process control.
Implementation Method 1
an air supply coupled to a solenoid valve used to control a pneumatically-operated emergency isolation valve (ZV)
Implementation Method 2
a second air flow path through the manifold connects the air supply to the solenoid valve through the smart valve positioner
Data Source
AI summary
An emergency shutdown (ESD) system for a process control system includes an air supply coupled to a solenoid valve used to control a pneumatically-operated emergency isolation valve (ZV) via a switchover kit, a smart valve positioner coupled to the solenoid valve via the switchover kit, and an ESD controller. The ESD controller is configured to: control the supply of air from the air supply by the solenoid valve to open and close the ZV, and control the smart valve positioner so as to perform a partial stroke test on the ZV. The switchover kit includes a manifold having a plurality of valves coupling the air supply, the solenoid valve, and the smart valve positioner such that: based on a first setting of the plurality of valves, a first air flow path through the manifold connects the air supply directly to the solenoid valve, and based on a second setting of the plurality of valves, a second air flow path through the manifold connects the air supply to the solenoid valve through the smart valve positioner.