Actuator Control Valve Spool with Differential Land Area
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Solution Overview
Problem
Existing actuator control valves lack efficient mechanisms to manage fluid communication and pressure changes without electrical signals, leading to potential unintended actuations and lack of self-containment in control systems.
Innovation Solution
A valve design with a spool and housing configuration that includes axially spaced lands and a third land with greater dimensions, along with a sensing assembly and actuator system that uses fluid pressure changes to control valve positions, ensuring fluid-tight separation and self-contained operation without external power.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a conventional actuator control valve is used without electrical signals for control, then the system achieves self-containment and independence from external power, but the valve lacks precise control mechanisms leading to potential unintended actuations
Solution Approach 1:
The valve system uses its own process fluid to provide control signals through pressure changes, eliminating the need for external electrical power or control systems. The process fluid itself serves the dual purpose of both medium being controlled and control signal carrier, achieving self-containment while maintaining precise control through the spool mechanism responsive to pressure differentials
Solution Approach 2:
The invention employs pneumatic/hydraulic pressure changes within the valve housing to control the spool position and thereby control fluid communication. Pressure signals from the process fluid actuate the spool to open or close fluid paths, providing precise mechanical control without electrical components
2Manufacturing precision
If the spool is made with larger cross-sectional dimensions to improve control precision, then the valve achieves better fluid-tight separation and control accuracy, but the device complexity and manufacturing difficulty increase
Solution Approach 1:
The spool features a third land with cross-sectional dimensions greater than the first and second lands, creating localized areas of enhanced sealing and control precision where needed. This non-uniform geometry provides improved fluid-tight separation at critical interfaces while maintaining simpler dimensions in other areas, optimizing the balance between precision and manufacturability
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
The solution enables precise control of fluid communication and actuator states based on pressure changes, preventing unintended actuations and ensuring self-contained operation, independent of electrical signals, thus enhancing system reliability and safety.
Implementation Method 1
fluid pressure changes to control valve positions
Data Source
AI summary
A spool valve is formed from a spool having two adjacent lands of equal cross-sectional dimensions, and a third land having greater cross-sectional dimensions than the other two. The spool reciprocably moves through a bore formed in a housing, so as to open and close fluid communication between selected pairs of ports formed in the housing. The bore includes a first chamber which receives the third land of the spool and has no externally communicating port formed in its walls. The spool valve may be used as a control valve for the actuator of a system valve. As the spool valve begins to actuate, the third land becomes exposed to actuator pressure. The greater area of the third land serves to increase the force applied to the spool valve by the actuator pressure source, enhancing protection from unintended or malicious resetting of the spool.