Aircraft Valve Baulking Tab Arrays Prevent Clamp Leakage
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Solution Overview
Problem
Aircraft valve assemblies lack structural features to prevent the installation of lighter duty V-band clamps, leading to excessive leakage and decreased engine efficiency due to the potential mistaken use of lighter duty clamps instead of heavier duty clamps in high-pressure, high-temperature applications.
Innovation Solution
Incorporating an array of baulking tabs around the valve assembly's ported end portion at predetermined intervals corresponding to the gap spacing of the desired clamp type, which physically limits the installation to the selected type of clamp, such as heavy duty V-band clamps with three segments, while preventing lighter duty clamps.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If no structural features are provided to prevent lighter duty clamp installation, then the device complexity is reduced and ease of manufacture is improved, but the reliability deteriorates due to potential mistaken installation of lighter duty clamps leading to excessive leakage
Solution Approach 1:
The baulking tabs are pre-installed on the flowbody flange before clamp installation. These tabs protrude radially outward and are positioned to interfere with lighter duty clamps having fewer segments. The preliminary placement of these structural features ensures that only clamps with the correct number of segments (matching the tab spacing) can be properly installed, preventing mistaken installation of inadequate clamps that would cause leakage.
Solution Approach 2:
The baulking tabs provide localized structural features at specific circumferential positions on the flowbody flange. Rather than making the entire flange complex, only specific localized areas have protruding tabs that encode the required clamp segment information. This localized approach adds minimal complexity while effectively communicating the required clamp type through the spatial arrangement of tabs.
2Reliability
If baulking tabs are added to prevent incorrect clamp installation, then the reliability is improved by ensuring correct clamp type, but the ease of manufacture deteriorates due to additional manufacturing steps
Solution Approach 1:
The solution divides the clamp assembly system into distinct functional elements: the flowbody flange with integrated baulking tabs, and the multi-segment clamp. The baulking tabs themselves are segmented features positioned at specific intervals around the flange perimeter. This segmentation allows the manufacturing process to add tabs as discrete elements rather than requiring complete redesign of the flange, simplifying the addition of this reliability feature.
Solution Approach 2:
The baulking tabs are incorporated into the flowbody flange manufacturing process itself, rather than being added as separate post-processing components. By including tab formation as part of the flange fabrication (through machining or molding operations already required for flange production), the solution avoids adding significant manufacturing complexity while ensuring the tabs are precisely positioned to verify clamp type.
3Loss of energy
If the flowbody is designed without preventive features, then the manufacturing cost is reduced, but the loss of energy increases due to potential excessive leakage across the flange interface
Solution Approach 1:
The baulking tabs are pre-positioned on the flowbody flange to prevent incorrect clamp installation before the system operates. By establishing the correct clamp type through physical interference from the tabs, the system ensures proper sealing from the outset, preventing energy loss through leakage. This preliminary preventive measure avoids the need for complex monitoring or adjustment systems during operation.
Solution Approach 2:
The baulking tabs provide self-verifying functionality through their geometric arrangement. The spacing and positioning of tabs automatically communicate the required clamp segment count to the installer through physical compatibility - only clamps with matching segment counts can be installed. This self-service mechanism eliminates the need for external verification systems, labels, or complex design features, keeping the overall device complexity low while preventing energy loss.
Data Source
AI summary
Embodiments of an aircraft valve assembly are provided for use in conjunction with a selected type of clamp having multiple segments separated by a predetermined gap spacing. In one embodiment, the aircraft valve assembly includes a flowbody having a ported end portion and a flow passage in which a valve element is movably mounted. An array of baulking tabs is mounted around the ported end portion at predetermined intervals corresponding to the predetermined gap spacing to substantially limit the type of clamps installable around the ported end portion to the selected type of clamp.