Segmented Bolt Structure for Turbine Casing Security
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Solution Overview
Problem
Conventional measures for preventing bolt members from falling out in turbines, such as welding or using locking pins, are inadequate in narrow workspaces and can lead to bolt members flying around and damaging turbine blades due to high-speed rotation, especially when the turbine operates long-term.
Innovation Solution
A bolt fall-out preventing structure that includes a first member with a first hole, a first bolt member inserted into the first hole to fix the first member to a support member, and a second member with a second hole, where a second bolt member is inserted to engage with the first member, suppressing changes in relative positions and preventing bolt movement by a wall portion on the second bolt member.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If conventional measures such as welding or locking pins are used to prevent bolt members from falling out, then the bolt members can be secured, but the wall thickness is reduced due to the working fluid flowing in the casing, leading to bolt members falling out after long-term operation
Solution Approach 1:
The invention divides the bolt member into two separate components: a first bolt member that passes through the first member and a second bolt member that engages with the first member. This segmentation allows the first bolt member to be secured without requiring welding or locking pins that would reduce wall thickness, while the second bolt member provides additional security through engagement. The segmented design maintains structural integrity while preventing bolt fall-out over long-term operation.
2Reliability
If measures for preventing falling out such as welding the bolt head or using a locking pin are implemented, then the bolt members can be secured, but the work space for implementing these measures is narrow depending on the fixing location and tightening direction
Solution Approach 1:
By segmenting the bolt member into two separate components with different functions, the invention enables the first bolt member to be installed using a standard insertion method that requires minimal workspace. The second bolt member, which engages with the first member, can be installed from the opposite side, effectively utilizing the narrow workspace between the first member and the casing without requiring welding or complex locking mechanisms.
3Power
If the turbine operates at high speed, then power generation efficiency is improved, but the turbine blade may become damaged by the bolt members that are flying around due to long-term operation
Solution Approach 1:
The segmented bolt member design with engagement between the first and second bolt members creates a mechanically interlocked system that prevents bolt loosening and fall-out during high-speed turbine operation. The engagement mechanism ensures that even under centrifugal forces and vibrations at high rotational speeds, the bolt members remain securely in place, eliminating the risk of flying bolts damaging turbine blades while maintaining power generation efficiency.
Data Source
AI summary
A bolt fall-out preventing structure includes: a first member, a first hole (13) being formed in the first portion (14) and the second portion (15); a first bolt member including a first head portion inserted into the first hole of the first member and disposed on the second portion, the first bolt member fixing the first member to a support member; a second member including a third portion and a fourth portion, the second member engaging with the first member; a second bolt member including a second head portion that opposes the first head portion; and a wall portion on the second head portion, the wall portion being disposed between a side surface of the first head portion and the second portion.