Flexible Fluid Conduit Joint with Blade Flexure Constraint
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Solution Overview
Problem
Existing flexible fluid conduit joints face challenges with excessive stress and weight issues due to expansion under pressure, and constraining methods often limit flexibility and add weight.
Innovation Solution
A flexible fluid conduit joint design incorporating a bellows with a constraint system of blade flexures or plates that constrain longitudinal expansion while allowing preferential bending about a specific axis, allowing multiple sections with differently oriented bending axes to be joined for enhanced flexibility without axial expansion.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If bellows are used to provide flexibility in fluid lines, then the ability to accommodate displacement and bending is improved, but the bellows expand under pressure causing additional stresses and reducing reliability
Solution Approach 1:
The constraint system is divided into multiple discrete blade flexures or plates distributed around the bellows circumference. Each blade independently constrains expansion while allowing bending, distributing the constraint function across multiple segments rather than using a continuous constraint structure.
Solution Approach 2:
The blade flexures are positioned at specific locations around the bellows circumference to provide constraint only in the axial expansion direction, while leaving other directions free for bending movement. This localized constraint approach allows the bellows to bend freely while preventing harmful axial expansion under pressure.
2Reliability
If stronger material is used for bellows to handle increased pressures, then reliability is improved, but weight increases and expansion ability is reduced
Solution Approach 1:
The blade flexures provide preliminary constraint against axial expansion before the bellows material must bear the full pressure load. By preventing expansion in advance, the system reduces the stress that would otherwise require stronger (and heavier) bellows material to withstand.
3Reliability
If an overbraid is added to constrain bellows expansion, then reliability under pressure is improved, but weight increases significantly and flexibility is reduced
Solution Approach 1:
The blade flexures are designed as thin, flexible elements that provide constraint through their geometric configuration rather than through heavy material construction. Each blade is a thin plate or flexure that bends easily to allow conduit bending while maintaining rigidity in the axial direction to prevent expansion.
4Reliability
If constraint systems are added to prevent bellows expansion, then reliability is improved, but the flexibility and bending capability of the conduit is reduced
Solution Approach 1:
The blade flexures are designed with different stiffness characteristics for different movement directions. They provide rigid constraint in the axial direction to prevent expansion, while being sufficiently flexible to allow bending movements of the bellows in radial directions. This anisotropic flexibility allows the system to adapt its constraint properties based on the direction of applied forces.
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 a lightweight, reliable, and low-stress flexible joint that maintains high reliability and flexibility, suitable for applications like cryocoolers, with the ability to achieve six degrees of freedom in conduit placement without significant expansion under pressure.
Implementation Method 1
a constraint system mechanically coupled to the bellows. The constraint system constrains expansion of the bellows in an axial direction
Implementation Method 2
the bellows expand when a pressurized fluid is run through them
Implementation Method 3
the blade flexures or plates allow preferential bending of the bellows about a preferential bending axis
Data Source
AI summary
A flexible fluid conduit joint includes two or more flexible sections that preferentially bend about respective preferential bend axes of the sections. The sections each include a flexible bellows coupled at longitudinal ends to a pair of annular collars, and a pair of blade flexures or plates that are also attached to the annular collars. The blade flexures or plates prevent longitudinal expansion of the bellows, and inhibit bending of the flexible sections about an axis that is perpendicular to the plane or planes that the flexures define. Flexing of each section is thus preferentially channeled into a preferentially bending axis within or parallel to the plane or planes defined by the flexures. The sections have different orientations for their blade flexures or plates, allowing the flexible joint to act as a two-axis pivot that does not expand under fluid pressure.