Pressure Relief Valve Geometry for Stable Aircraft Anti-Ice Regulation
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Solution Overview
Problem
Current pressure relief valves in aircraft anti-ice systems suffer from spurious phenomena such as oscillations, hysteresis, and loss of calibration due to inaccuracies in manufacturing and airflow path design, leading to output inaccuracy.
Innovation Solution
A pressure relief valve design featuring a plunger with a low diameter-to-length ratio, inclined discharge ports, and an anti-rotation washer to improve plunger guidance, compensate for spring tolerances, and optimize airflow, reducing side loads and turbulence.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If a conventional plunger design with higher diameter-to-length ratio is used, then the valve structure is simpler and easier to manufacture, but the valve produces oscillations, hysteresis, and loss of calibration leading to output inaccuracy
Solution Approach 1:
The patent changes the geometric parameters of the plunger by significantly reducing the diameter-to-length ratio to less than 1:2 (preferably about 1:4). This parameter change transforms the plunger from a conventional short and stout shape to a long and slender form, which fundamentally alters the flow characteristics and eliminates spurious phenomena such as oscillations and hysteresis, thereby improving output accuracy.
2Productivity
If discharge ports are oriented perpendicular to the longitudinal axis, then the valve structure is simpler, but the airflow path creates turbulence and reduces discharge efficiency
Solution Approach 1:
The patent applies dynamic flow optimization by orienting the discharge ports at an angle between 10 and 45 degrees relative to the longitudinal axis of the valve housing. This angular orientation dynamically aligns the discharge ports with the natural flow direction of the fluid, reducing turbulence and improving discharge efficiency compared to conventional perpendicular orientations.
3Reliability
If the plunger is not properly guided, then the valve structure is simpler, but the plunger experiences side loads and calibration drift
Solution Approach 1:
The patent introduces guiding surfaces as intermediary elements between the plunger and the valve housing. These guiding surfaces, positioned at specific locations along the plunger length, provide lateral support and constraint without requiring complex mechanical guidance structures. The intermediory guiding surfaces distribute side loads and maintain plunger alignment, ensuring calibration stability.
4Reliability
If the plunger has high diameter-to-length ratio, then the spring force is more effective, but the valve generates oscillations and hysteresis
Solution Approach 1:
The patent changes the plunger geometry parameters by reducing the diameter-to-length ratio to less than 1:2, which fundamentally alters the force transmission characteristics. This parameter change reduces the effectiveness of spring force alone but eliminates oscillations and hysteresis by creating a more stable flow regime, thereby achieving better overall reliability.
Data Source
AI summary
A new type of pressure relief valve is described herein which has advantages over standard valves in that it may comprise a longer plunger than normal, and two guiding points located far away from each other for guiding the plunger within the housing. The valve may also comprise improved exhaust ports and an anti-rotation washer.