Hydraulic Trip Valve Actuator for Online Dump Valve Testing
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Traditional trip and throttle valve (TTV) designs for steam turbines lack the ability to test every moving element of the actuator without tripping the system, often require large return springs for high-speed trip functions, and are prone to sticking due to contamination, especially in commercial offerings.
Innovation Solution
A fluid actuator system with moveable plates and bias members that allow sequential testing of all critical components, including dump valves, while maintaining the system in an un-tripped state, enabling on-line testing and easy scalability, and providing resistance to contamination.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If traditional TTV designs are used with manual test valve handles, then the actuator can be partially tested on-line, but the large dump valve cannot be tested without tripping the system
Solution Approach 1:
The actuator is divided into multiple independent testable sections with separate test valves for each dump valve (first dump valve test valve and second dump valve test valve). This segmentation allows each component to be tested independently without affecting the entire system or requiring a full trip condition.
Solution Approach 2:
Test valves are introduced as intermediary components that provide a controlled path for testing dump valves without requiring actual trip conditions. These test valves act as mediators between the operator and the dump valves, enabling safe on-line testing of all moving elements including the large dump valves that previously could not be tested without tripping the system.
2Speed
If large return springs are used to provide high-speed trip function, then adequate trip time is achieved, but the actuator size and weight increase
Solution Approach 1:
The patent replaces mechanical return springs with a hydraulic system using hydraulic fluid to provide the trip function. The hydraulic system uses fluid pressure to actuate the piston, eliminating the need for large return springs while maintaining high-speed trip capability. This reduces actuator weight and size while achieving the required trip performance.
3Reliability
If traditional TTV designs are used, then the system can operate, but it is prone to sticking when operating in contaminated oil
Solution Approach 1:
The patent modifies the operational parameters of the actuator by using hydraulic fluid with controlled properties and maintaining specific pressure conditions that prevent contamination from causing sticking. The hydraulic system operates at parameters that minimize the harmful effects of contamination, allowing reliable operation even in contaminated environments.
Solution Approach 2:
The patent converts the potential harm of contaminated oil into a non-problematic condition by designing the hydraulic system to tolerate and operate reliably in contaminated environments. The system design transforms the previously harmful contamination into an acceptable operating condition, eliminating the sticking problem while maintaining operational reliability.
4Ease of operation
If manual hand wheel operation is used for valve opening, then the throttling function is achieved, but the operation requires manual intervention and is time-consuming
Solution Approach 1:
The patent replaces the manual mechanical hand wheel operation with an automated hydraulic system. The hydraulic actuator uses fluid pressure to automatically open and close the valve, eliminating the need for manual hand wheel operation. This substitution reduces operational time and effort while maintaining the throttling function, allowing faster turbine startup and shutdown operations.
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 comprehensive testing of trip and throttle valve components without tripping the turbine, allows free movement in the un-tripped state, is easily scalable, and offers increased resistance to contamination, enhancing the reliability and maintainability of the system.
Implementation Method 1
a piston having a piston head configured to fluidically seal against the first inner wall and configured to move axially along a portion of the first inner wall
Implementation Method 2
an annular cavity defined between the outer cylindrical housing and the inner cylindrical housing, a first moveable plate configured to fluidically seal against the second inner wall and configured to move axially along a first portion of the second inner wall
Data Source
AI summary
The subject matter of this specification can be embodied in, among other things, a fluid actuator system including a fluid actuator having a housing having an inner wall defining an interior cavity, a piston having a piston head configured for reciprocal movement within the interior cavity, the piston head contacting the inner wall and dividing the interior cavity into a first fluid chamber and a second fluid chamber, a first valve configured to control fluid flow between the first fluid chamber and a bypass conduit, and a second valve configured to control fluid flow between the bypass conduit and the second fluid chamber.