PRSOV Pneumatic Actuator Asymmetry for Predictable Power-Loss Shutoff
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Solution Overview
Problem
Pressure regulating shut-off valves (PRSOVs) in aircraft engine anti-ice systems face challenges in ensuring a reliable shut-off function, particularly when power is lost, which is critical for flight safety.
Innovation Solution
A pressure regulating shut-off valve design incorporating a pneumatic actuator with a piston having unequal surface areas and an electrically actuated valve that restricts or opens a fluid path, allowing the pneumatic actuator to hold the valve member in a fixed position when power is removed, ensuring a predictable shut-off function.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a conventional PRSOV design is used, then the valve can regulate pressure during normal operation, but the shut-off function becomes unpredictable when power is lost
Solution Approach 1:
The patent inverts the conventional approach by designing the pneumatic actuator with unequal piston surface areas so that the valve member automatically moves to a predetermined position (open or closed) when pneumatic pressure is lost, rather than requiring active control power to maintain position. This passive failsafe mechanism ensures predictable shut-off behavior without requiring powered operation.
Solution Approach 2:
The pneumatic actuator utilizes the existing pneumatic pressure from the inlet line to automatically position the valve member in a failsafe state when power is lost. The system serves itself by using the process fluid's own pressure to ensure reliable shut-off, eliminating the need for external backup systems or additional control power.
2Extent of automation
If an electrically actuated valve is used to control the fluid path, then the valve can be precisely controlled during operation, but the system requires continuous power supply to maintain control
Solution Approach 1:
The electrically actuated valve is configured to close the fluid path to the second volume in advance when power is supplied, preparing the pneumatic actuator for automatic failsafe operation. This preliminary action ensures that when power is lost, the valve member is already positioned to move to the predetermined safe state without requiring additional energy input.
Solution Approach 2:
The patent replaces the need for continuous electrical power to maintain valve position with a mechanical/pneumatic system that uses pressure differential across the unequal piston surfaces. The pneumatic actuator mechanically ensures valve positioning based on pressure conditions, substituting active electrical control with passive pneumatic-mechanical operation.
3Stability of the object's composition
If equal surface areas are used on both faces of the piston, then the actuator operates symmetrically, but the valve member cannot be reliably held in a fixed position during power loss
Solution Approach 1:
The patent deliberately introduces asymmetry by making the second face of the piston have a greater surface area than the first face. This asymmetric design creates a pressure differential effect that generates force to move the valve member to a predetermined position when pneumatic pressure is lost, ensuring reliable and stable valve positioning during power loss conditions.
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
This design provides a reliable failsafe mechanism that maintains a defined position of the valve member when power is lost, preventing fluid supply disruptions to the anti-ice system and ensuring flight safety.
Implementation Method 1
The second face of the piston has a surface area that is greater than a surface area of the first face of the piston... the pneumatic actuator is arranged to act on the valve member, when power is removed from the electrically actuated valve, to hold the valve member in a fixed position
Implementation Method 2
The electrically actuated valve is arranged to restrict or substantially close the fluid path between the inlet of the pressure regulating shut-off valve and the second volume
Data Source
AI summary
A pressure regulating shut-off valve has a valve member regulating flow of fluid between an inlet and an outlet. The valve includes a pneumatic actuator having a piston having first and second faces that define first and second volumes within a cylinder. The second face has a greater surface area than the first face. The first and second volumes are fluidly connected to the inlet, and an electrically actuated valve controls the flow of fluid along a fluid path to the second volume. The electrically actuated valve closes the fluid path, when power is supplied to the electrically actuated valve, and opens the fluid path, when power is removed from the electrically actuated valve, which causes the pneumatic actuator to act on the valve member to hold the valve member in a fixed position.