Double-Walled Tube Fitting With Threaded Leakage Channel
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Solution Overview
Problem
Gas turbine engines face challenges in effectively lubricating moving parts within the compressor, combustor, and turbine sections, where double-walled tubes are used to transport lubricating fluids, but existing fittings do not efficiently manage fluid leakage and threading configurations can complicate assembly and maintenance.
Innovation Solution
A fitting system comprising an inner and outer fitting with weld lips, threading, and bump-outs that form a channel for fluid flow, along with an outward protrusion for tool interface, allowing for efficient fluid transport and leakage management, and facilitating assembly through mating threading and hexagonal protrusions.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If traditional single-piece fittings are used in double-walled tubes, then manufacturing is simpler, but fluid leakage cannot be effectively managed and lubrication efficiency decreases
Solution Approach 1:
The fitting is divided into two separate pieces: an inner fitting that interfaces with the inner tube and an outer fitting that interfaces with the outer tube. This segmentation allows each piece to be optimized for its specific function - the inner fitting for fluid transport and the outer fitting for containment - thereby effectively managing fluid leakage while maintaining reasonable manufacturing complexity
Solution Approach 2:
The inner fitting is nested within the outer fitting, with the inner fitting positioned inside the outer fitting's internal cavity. This nested configuration allows the double-walled tube structure to be formed by welding both fittings to their respective tubes, creating a sealed environment that prevents fluid leakage from the inner tube to the external environment
2Strength
If complex threading configurations are used in fittings, then connection strength is improved, but assembly and maintenance difficulty increases
Solution Approach 1:
The threading system is segmented into two distinct threading configurations: first threading on the outer surface of the inner fitting and second threading on the inner surface of the outer fitting. This segmentation allows each threading to be optimized independently - the outer threading for strong connection to the inner tube, and the inner threading for easy engagement with the outer tube - thereby maintaining connection strength while simplifying assembly and maintenance operations
Data Source
AI summary
A fitting for forming a double-walled tube includes an inner fitting having a first inner weld lip, a second inner weld lip, and an inner body extending from the first inner weld lip to the second inner weld lip and having an outer surface with a first threading. The fitting also includes an outer fitting having a first outer weld lip, a second outer weld lip, and an outer body extending from the first outer weld lip to the second outer weld lip and having an inner surface with a second threading that is configured to mate with the first threading.