Semi-Permeable Drain Valve for Aircraft Light Condensation Control
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Solution Overview
Problem
Exterior aircraft light units face issues with excessive pressure and water condensation due to varying air pressure during flight, leading to potential deterioration of functionality from excessive water accumulation.
Innovation Solution
A drain valve with a movable plunger and semi-permeable membrane that allows air and water vapor to pass while preventing liquid water entry, and automatically opens to drain excess water when pressure equalizes, ensuring effective venting and drainage without external control.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Stress or pressure
If the exterior aircraft light unit is vented during flight to equalize pressure, then pressure balance is achieved, but water vapor condensation occurs leading to water accumulation inside the light unit
Solution Approach 1:
The patent employs a semi-permeable membrane that acts as a porous material allowing selective passage of substances. The membrane permits air and water vapor to pass through during pressure equalization while blocking liquid water, thus resolving the contradiction between achieving pressure balance and preventing water accumulation inside the light unit
Solution Approach 2:
The semi-permeable membrane serves as an intermediary element between the interior of the light unit and the external environment. It mediates the pressure equalization process by allowing gas exchange while preventing liquid water ingress, and works in conjunction with the drain valve system to remove condensed water
2Quantity of substance
If a drain valve is added to drain condensed water, then water removal capability is improved, but device complexity increases
Solution Approach 1:
The drain valve is designed with a floating ball mechanism that automatically opens and closes based on water level. When water accumulates, the ball rises and opens the valve to drain water; when water level drops, the ball falls and closes the valve. This self-regulating mechanism eliminates the need for external control systems, sensors, or complex actuators
Solution Approach 2:
The invention extracts the essential draining function from complex automated valve systems and implements it through a simple passive mechanical mechanism. The floating ball valve extracts only the necessary water removal capability while eliminating unnecessary complexity, achieving water drainage through basic buoyancy principles
3Object-affected harmful factors
If the light unit housing is made completely sealed to prevent water ingress, then water protection is improved, but pressure equalization capability deteriorates
Solution Approach 1:
The housing is designed with local quality differentiation: the majority of the housing structure is completely sealed to prevent water ingress and protect internal components, while specific localized areas incorporate the semi-permeable membrane and drain valve assembly. This allows the housing to simultaneously achieve water protection and pressure equalization capability
Solution Approach 2:
The venting system is segmented into multiple functional components: the sealed housing structure, the semi-permeable membrane for selective gas exchange, and the drain valve assembly for liquid water removal. This segmentation allows each component to perform its specific function while collectively resolving the contradiction between sealing and pressure equalization
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 provides reliable and cost-effective venting and drainage for exterior aircraft light units and power supply boxes, preventing water ingress and reducing the risk of explosions from hot gases, while maintaining efficient operation.
Implementation Method 1
said at least one duct is sealed by a semi-permeable medium, which is permeable for air and water vapor in case a predetermined pressure difference is exceeded, and which is impermeable for liquid water
Implementation Method 2
an elastic element, which is configured to urge the movable plunger into its closed position
Implementation Method 3
When positioned in an open position, the plunger allows liquid to flow through the drain valve
Data Source
Figure 1A~1B
Figure 2~3
Figure 4~5
AI summary
A drain valve (20) for draining liquid from an enclosed space (14) comprises a movable plunger (42), which is movable between a closed position in which the plunger (42) does not allow liquid to flow through the drain valve (20), and at least one open position, in which the plunger (42) allows liquid to flow through the drain valve (20); and an elastic element (40; 54), which is configured to urge the movable plunger (42) into its closed position. The plunger (42) is provided with at least one duct (44) extending through the plunger (42) and allowing fluid to flow through the drain valve (20) when the plunger (42) is positioned in its closed position, wherein said at least one duct (44) is closed by a semi-permeable medium (48), which is permeable for air and water vapor and impermeable for liquid water.