Vent Valve for Rotary Propeller Pitch Lock
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Solution Overview
Problem
Rotary aircraft propeller pitch control assemblies experience pressure loss, leading to loss of thrust due to inability to maintain propeller blade pitch, necessitating a solution to lock pitch until pressure is restored.
Innovation Solution
A fluid actuated vent valve system with a sensing sleeve and piston, and a shutoff spool that moves between locked and unlocked positions to control fluid flow, minimizing parasitic fluid loss and improving responsiveness by allowing fluid flow into a vent channel during movement, and restricting flow when in specific positions to maintain pitch.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Stability of the object's composition
If a propeller pitch lock is used to maintain pitch during pressure loss, then pitch stability is improved, but responsiveness to pressure restoration is worsened
Solution Approach 1:
The pitch control system is divided into separate functional components: a pitch lock mechanism for stability during pressure loss, and a vent valve with sensing piston for rapid detection and response to pressure restoration. This segmentation allows each component to optimize its function without compromising the other.
Solution Approach 2:
The vent valve and sensing piston are pre-positioned and ready to act immediately upon pressure restoration. The sensing piston is already in place to detect pressure changes, and the vent valve is prepared to rapidly vent fluid and adjust pitch, eliminating delays in response.
2Stability of the object's composition
If fluid flow is restricted to maintain pitch during pressure loss, then pitch stability is improved, but energy loss is worsened
Solution Approach 1:
The harmful parasitic fluid loss is extracted and eliminated by designing a system where the pitch lock and vent valve work together to prevent unnecessary fluid circulation. The vent valve specifically targets and removes only the harmful fluid loss while maintaining the beneficial pitch stability.
Solution Approach 2:
The system discards (vents) fluid only when necessary for pitch adjustment, rather than continuously restricting flow. The vent valve opens to discard excess fluid that would otherwise cause parasitic loss, while maintaining pitch stability through controlled operation.
3Speed
If a vent channel is provided for venting fluid, then responsiveness is improved, but fluid loss is worsened
Solution Approach 1:
The vent valve dynamically controls the vent channel opening based on real-time pressure conditions and pitch requirements. The sensing piston automatically adjusts the vent channel opening degree, allowing rapid fluid venting when needed for responsiveness while minimizing fluid loss during normal operation.
Solution Approach 2:
The sensing piston provides continuous feedback on pressure conditions to the vent valve, enabling automatic adjustment of the vent channel opening. This feedback mechanism ensures the vent channel opens only when necessary, improving responsiveness while preventing unnecessary fluid loss.
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 system effectively locks propeller blade pitch during pressure loss, reducing energy consumption and enhancing responsiveness by minimizing fluid loss and allowing quick adjustment when pressure is restored, thus maintaining thrust.
Implementation Method 1
A vent valve (33) is provided having a sensing sleeve (42) and a sensing piston (43). The sensing piston (43) is moveable within a sensing chamber (62) between an open and closed position in response to a change in flow of a fluid
Data Source
AI summary
A vent valve (33) according to an exemplary aspect of the present disclosure includes, among other things, a sensing sleeve (42) defining a sensing chamber (62) and a vent channel (66) for venting fluid out of the sensing chamber (62). A sensing piston (43) is moveable within the sensing chamber (62) between an open position and a closed position. The sensing piston (43) allows flow of the fluid into the vent channel (66) during movement of the sensing piston (43) between the open and closed positions.