Aircraft Check Valve Hinge Pin Retention Design
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Solution Overview
Problem
Check valves in aircraft air conditioning systems face issues with the loosening or detachment of securing elements, leading to improper operation or failure, as existing hinge pin arrangements are not secure enough.
Innovation Solution
A modified check valve design featuring a central mounting post with transverse and longitudinal bores, aligned with mounting posts' bores, and a hinge pin locking retaining element, secured by a fastener, which prevents hinge pin retraction and provides a stop for flapper elements, ensuring secure fluid flow directionality.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the transverse bore in the mounting post is fully closed, then the hinge pin is securely retained, but access to the end of the hinge pin becomes difficult for inspection and maintenance
Solution Approach 1:
The transverse bore is made partially closed rather than fully closed - it has sufficient length to securely retain the hinge pin and prevent detachment, but not so long that it creates excessive material removal or manufacturing complexity. The bore opens at the end to allow hinge pin insertion while providing enough enclosed length for secure retention
Solution Approach 2:
The extended end portion of the hinge pin acts as an intermediary element that bridges the sealed transverse bore and the external environment. It allows the bore to be sealed for retention while the extended portion provides access points for inspection and maintenance without compromising the security of the hinge pin mounting
2Strength
If stronger materials are used for critical components like the hinge pin and mounting posts, then the security and durability of the hinge pin arrangement is improved, but the weight of the valve increases
Solution Approach 1:
Stronger materials are applied locally only to critical components where high strength is required - specifically the hinge pin and mounting posts that bear the mechanical loads. Other non-critical components of the valve can use lighter materials, achieving optimal strength-to-weight ratio by concentrating material strength where it is most needed
Data Source
AI summary
A check valve comprises a valve housing defining a valve opening and a web extending across the valve opening. First and second mounting posts are provided on the valve housing on opposite sides of the opening and extend away from the opening. Each mounting post has a transverse bore formed therein.