Automatic Speed Searching Device for Control Valve Partial Stroke Testing
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Current process control systems lack a simple and cost-effective method to monitor the performance of control valves without positioners, which are essential for determining optimal stroke speeds during partial stroke tests.
Innovation Solution
An automatic speed searching device comprising a spool valve, pilot valve, blocker valve, and electrical module that iteratively adjusts solenoid power to determine optimal stroke speeds for control valve movement between open and closed positions, eliminating the need for positioners or limit switches.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If a positioner is used to determine optimal stroke speeds for control valves, then measurement precision and diagnostic capability are improved, but device complexity and cost increase
Solution Approach 1:
The patent extracts the speed search functionality from the positioner and implements it as a separate, independent device. This allows the speed determination function to be added without requiring the complex positioner hardware, thereby reducing device complexity while maintaining measurement precision through dedicated speed search circuitry and algorithms
Solution Approach 2:
The patent introduces an intermediary speed searching device that acts as a bridge between the simple on/off valve control and the complex positioner. This intermediary device provides the necessary diagnostic capabilities by measuring stem speed and position without requiring full positioner functionality, thus improving measurement precision while limiting device complexity
2Reliability
If iterative speed searching is performed to determine optimal stroke speeds, then diagnostic capability is improved, but loss of time increases
Solution Approach 1:
The patent performs preliminary actions by first determining the full-stroke time of the valve, then using this information to calculate and set appropriate pulse widths for partial stroke testing. This preliminary characterization allows subsequent diagnostic tests to be performed more efficiently with pre-determined optimal speeds, reducing the time loss during actual diagnostic operations
Solution Approach 2:
The patent employs periodic action through iterative speed searching where the valve is cycled through multiple test strokes at different speeds. The system periodically adjusts the pulse width and tests different stroke speeds until the optimal speed is found. This periodic testing approach systematically improves diagnostic capability while limiting time loss through structured, repetitive testing patterns
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 precise determination of optimal stroke speeds for control valves, enhancing diagnostic capabilities and maintenance efficiency without requiring positioners or additional hardware, making it suitable for various actuator types and sizes.
Implementation Method 1
The electrical module includes a main solenoid communicatively connected to the pilot valve and a secondary solenoid communicatively connected to the blocker valve
Implementation Method 2
a pilot valve configured to position the spool valve to one of an open position and a closed position
Implementation Method 3
the spool valve includes a first control fluid inlet, a first control fluid outlet, and a second control fluid outlet, the first control fluid inlet being fluidly connected to a supply of control fluid
Data Source
AI summary
An automatic speed searching device for a partial stroke test of a control valve includes a spool valve operatively connected to a pilot valve and a blocker valve. An electrical module is operatively connected to the pilot valve, a supply of control fluid, and the blocker valve. In an open position of the spool valve, a first control fluid inlet is fluidly connected to a first control fluid outlet, and in a closed position of the spool valve the first control fluid outlet is fluidly connected to a second control fluid outlet. A method of determining an optimum stroke speed includes iteratively powering a main and secondary solenoid in the electrical module and updating parameters to move a control element of the control valve until movement of the control element is within a desired range.