Flapper Valve Guide Legs and Self-Lubricating Seal Alignment
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Solution Overview
Problem
Flapper valve assemblies in fuel tanks face issues with misalignment and seal quality due to non-vertical orientation and sticking of the flapper member to the valve seat, affecting the sealing efficiency.
Innovation Solution
The flapper valve assembly incorporates guide legs and a self-lubricating seal with PTFE to maintain proper alignment and prevent sticking, using a guide ring and alignment structures to ensure coaxial alignment and a gimbal-type connection for free pivoting, along with a self-lubricating seal made from elastomeric materials like fluorosilicone with PTFE.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the flapper valve assembly is not maintained in a vertical orientation or if the flapper member becomes coaxially misaligned with the valve seat, then the sealing quality deteriorates, but the device must operate reliably in various orientations
Solution Approach 1:
The flapper member is designed to pivot and dynamically adjust its orientation to maintain coaxial alignment with the valve seat regardless of the assembly's installation angle. This dynamic adjustment capability allows the seal to adapt to different orientations while maintaining reliable sealing.
Solution Approach 2:
The guide structure incorporates asymmetric features that provide alignment guidance in all orientations. The guide surface is shaped to ensure the flapper member automatically orients itself correctly relative to the valve seat, preventing misalignment issues regardless of how the assembly is installed.
2Reliability
If the sealing surface of the flapper member sticks to the valve seat before the flapper member properly orients itself, then the sealing quality deteriorates, but increasing seal pressure improves sealing
Solution Approach 1:
A self-lubricating seal material is introduced as an intermediary between the flapper member and valve seat. This material reduces friction and prevents sticking, allowing the flapper member to smoothly orient itself onto the valve seat without premature adhesion that would cause misalignment.
Solution Approach 2:
The guide structure provides preliminary alignment of the flapper member with the valve seat before the sealing surfaces make full contact. This preliminary positioning ensures proper orientation is established before sealing pressure is applied, preventing sticking-induced misalignment.
3Reliability
If a typical seal material is used, then the manufacturing cost is low, but the seal sticks to the valve seat affecting sealing efficiency
Solution Approach 1:
The seal is constructed from composite material combining elastomeric base material with PTFE (polytetrafluoroethylene) particles dispersed throughout. This composite structure provides both the elasticity needed for sealing and the low-friction properties of PTFE that prevent sticking, achieving reliable sealing without significantly complicating manufacturing.
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 ensures reliable sealing by maintaining proper alignment and preventing sticking, enhancing the sealing efficiency and durability of the flapper valve assembly even in non-vertical orientations.
Implementation Method 1
the seal may be made from a self-lubricating material such as polytetrafluoroethylene (PTFE)
Implementation Method 2
a self-lubricating seal with PTFE to maintain proper alignment and prevent sticking
Data Source
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AI summary
A flapper valve assembly is provided for venting pressure in a tank. The flapper valve assembly includes a float assembly that is configured to be disposed within a valve housing. The float assembly may have a plurality of guide supports that extend from an end portion of the float assembly. A flapper member is movably supported on the float assembly. The flapper member may include a plurality of guide legs that correspond with the guide supports of the float assembly to maintain proper alignment of the flapper member relative to the float assembly.