Exhaust Liner Suspension Using Torque Bushings
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Solution Overview
Problem
The installation of exhaust duct liners in gas turbine engines with variable direction exhaust ducts, such as three bearing swivel ducts, is complicated by the need to insert fasteners into the interior of the duct from the exterior, leading to alignment issues and difficulties in securing the liners properly, especially due to the restricted diameter at swivel bearing joints.
Innovation Solution
A duct liner suspension system that includes torque bushings with tabs and a lock nut mechanism, allowing for secure attachment from the exterior while ensuring proper alignment and torque transfer, and featuring a design that can be inserted past swivel bearing joints during assembly, using materials like stainless steel or titanium for compatibility and thermal resistance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If fasteners are inserted into the interior of the duct from the exterior to secure exhaust duct liners, then the liners can be attached to the exhaust duct segments, but alignment difficulties occur and fasteners may drop into the exhaust duct
Solution Approach 1:
Instead of inserting fasteners from the exterior into the interior of the duct, the invention inverts the approach by providing fasteners that are inserted from the interior of the exhaust duct through openings in the liner to engage with retention members on the exhaust duct segments. This reversal eliminates alignment difficulties and prevents fastener loss.
Solution Approach 2:
The invention introduces retention members as intermediary elements that extend from the exhaust duct segments through openings in the liner. These retention members serve as mediators that receive and secure the fasteners from the interior, facilitating reliable attachment while simplifying the installation process.
2Reliability
If exhaust duct segments are assembled before attaching liners, then swivel bearing joints can be properly pre-loaded, but the restricted diameter at swivel bearing joints complicates liner insertion
Solution Approach 1:
The invention inverts the traditional installation sequence by attaching the liner to the exhaust duct segments from the interior side. Fasteners are inserted from inside the duct through liner openings to engage retention members, allowing liner attachment after duct assembly without complexity from exterior fastening.
Solution Approach 2:
The invention segments the attachment system into distinct components: retention members extending from exhaust duct segments, fasteners inserted through liner openings, and locking mechanisms. This segmentation allows each component to perform its function independently, simplifying the overall installation process.
3Reliability
If conventional fastening methods are used for exhaust duct liners, then attachment can be achieved, but installation time increases and proper alignment cannot be ensured
Solution Approach 1:
The retention members are pre-installed on the exhaust duct segments before liner attachment. This preliminary action ensures that when fasteners are inserted from the interior, they automatically engage with pre-positioned retention members, ensuring proper alignment and reducing installation time.
Solution Approach 2:
The fastening system is designed to be self-aligning and self-securing. Fasteners inserted from the interior automatically engage with retention members through the liner openings, and locking mechanisms automatically secure the connection, eliminating the need for complex alignment procedures or specialized installation tools.
Data Source
Figure 1
Figure 2A~2B
Figure 3
AI summary
A bushing (42) for assembling an exhaust duct liner (28) with an exhaust duct (26) in a gas turbine engine comprises a body, a bushing opening (64) and a tab (66). The body is insertable into a duct opening (52) in an exhaust duct (26). The bushing (42) opening receives a shaft (58) of a liner fastener (44), wherein the fastener (44) is connectable with a duct liner (28). The tab (66) extends into the duct opening (52) and prevents rotation of the liner fastener (44).