Hose End Fitting Retention for Cryogenic Fatigue
Solution Overview
Problem
Hose end fittings for cryogenic conditions face challenges in maintaining hose geometry and resisting fatigue and overbending, especially when used with flexible materials and high pressures, and require improved retention and sealing mechanisms.
Innovation Solution
The end fitting incorporates split ring-shaped inner and outer retaining members with gripping formations, a hose engaging member that clamps all layers securely, and a polymeric bend stiffener to address these issues, along with an integral load transferring member for enhanced fatigue resistance and secure anchoring of the axial reinforcing braid.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If flexible materials are used to maintain hose flexibility, then the hose can bend and flex, but the hose becomes prone to overbending and geometry loss
Solution Approach 1:
The hose employs a composite structure combining flexible polymeric layers with rigid axial reinforcing elements (wire braid or spiral wire). This composite construction allows the hose to maintain flexibility from the polymeric layers while the axial reinforcing elements prevent overbending and preserve geometric stability during flexing operations.
2Stress or pressure
If high pressure is applied to transport fluids, then fluid transport capability is improved, but the hose experiences excessive hoop deformation
Solution Approach 1:
The hose structure combines pressure-resistant features including helical wires wound at specific pitches and axial reinforcing elements that work together to resist hoop deformation under high pressure while maintaining the hose's operational pressure capability.
Solution Approach 2:
The helical wires are wound at optimized pitches around the hose circumference, creating a curved reinforcement pattern that effectively distributes and resists hoop stresses generated during high-pressure fluid transport, preventing excessive deformation.
3Ease of manufacture
If conventional end fitting retention methods are used, then assembly is simple, but the hose layers are not securely retained and fatigue resistance is poor
Solution Approach 1:
The end fitting employs a composite retention system combining an inner member with gripping formations that engage the hose layers, an intermediate sealing element, and an outer retaining member. This multi-layer composite structure secures the hose layers against fatigue and disassembly while maintaining manufacturing feasibility.
Solution Approach 2:
The inner member features localized gripping formations at specific positions along its length, providing enhanced retention at critical areas where the hose layers need secure anchoring, while other portions of the end fitting maintain simpler geometries for ease of assembly.
Data Source
AI summary
An end fitting (200) for terminating an end of a hose comprising a tubular body of flexible material arranged between inner and outer helical wires, characterized in that the end fitting comprises: an inner member (202) adapted to be disposed at least partially within the hose; and a hose engaging member (208) adapted to press against the inner member 202 to retain the hose between itself and the inner member (202). The end fitting also includes a separate means for retaining one or more layers of the hose, the retaining means comprising an outer retaining member (232) adapted to press against an inner retaining member (230) to retain the or each layer of the hose between the outer and inner retaining members (232, 230) of the retaining means.