Aircraft Fuel Tank Float Valve Pressure Regulation
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Solution Overview
Problem
Aircraft fuel tank vent systems face challenges in managing pressure changes during maneuvers, which can lead to damage or increased weight, as existing solutions either fail to prevent fuel transfer or require heavier tank structures to withstand pressure increases.
Innovation Solution
A pressure regulating float valve system that includes a conduit connecting the wing fuel tank and surge tank, with a buoyant member and seal plate mechanism that seals the opening when the fluid level rises and opens when pressure thresholds are exceeded, allowing pressure relief without fuel spillage.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If the tank structure is sized to withstand pressure increases, then the fuel tank can resist damage during maneuvers, but the weight of the airplane increases
Solution Approach 1:
The patent applies a dynamic pressure relief mechanism through a float valve that automatically opens and closes based on pressure conditions. The float valve allows the tank to adapt to pressure changes during maneuvers, maintaining structural integrity without requiring the tank to be permanently sized for maximum pressure withstand, thereby reducing unnecessary weight
Solution Approach 2:
The float valve acts as an intermediary pressure relief device between the fuel tank and the external environment. It mediates pressure buildup by opening to relieve pressure when thresholds are exceeded and closing to maintain pressure when safe, eliminating the need for the tank structure itself to be oversized for pressure resistance
2Reliability
If the float valve closes to prevent fuel transfer, then fuel remains in the wing tank during maneuvers, but pressure buildup may cause tank damage
Solution Approach 1:
The float valve mechanism changes its operational parameter (open/closed state) based on pressure conditions. It closes to prevent fuel transfer during normal maneuvers but automatically opens when pressure exceeds a threshold, and closes again when pressure returns to safe levels. This dynamic parameter change resolves the contradiction by allowing both fuel transfer control and pressure relief
Solution Approach 2:
The float valve performs periodic opening and closing actions in response to pressure fluctuations during maneuvers. This periodic action allows the system to maintain fuel transfer control while periodically relieving pressure buildup, preventing damage without requiring continuous opening that would compromise fuel transfer control
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 solution provides flexible tank design options, prevents fuel transfer during rotation, and effectively manages pressure changes, reducing the risk of damage and weight penalties by automatically regulating pressure through the float valve mechanism.
Implementation Method 1
when a buoyant member at a distal end rises along with the seal plate through the member with a rise in fluid level within the fuel tank
Implementation Method 2
a seal plate within the conduit sealing the opening into the fuel tank
Implementation Method 3
opens when pressure thresholds are exceeded, allowing pressure relief without fuel spillage
Data Source
Figure 1
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Figure 3
AI summary
A fuel tank (102) system for an aircraft has a vent system. The system has a conduit opening (108) into the fuel section. The system has a member (122) connected to the conduit (104) at a proximal end. The member has a seal plate (132) within the conduit (104) sealing the opening (108) into the fuel section when a buoyant section at a distal end rises along with the seal plate through the member (122) with a rise in fluid (124) level within the fuel section.