Radial Pin Fixing Device for Rotary Machine Sealing
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Solution Overview
Problem
The existing fixing devices for rotary machines, such as steam turbines, require time-consuming welding operations for attachment and detachment, which complicates the assembly and disassembly processes while compromising the sealing integrity.
Innovation Solution
A fixing device comprising a radial pin with a flange portion, a seal unit with a sleeve and insertion member, and a cap member that allows for easy attachment and detachment without welding, ensuring sealing integrity through a threaded structure and adjustable liner support.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If welding is used to fix the radial pin to the inner casing, then the sealing property is improved, but the attachment and detachment time increases
Solution Approach 1:
The fixing device is divided into separate components: a radial pin, a seal unit, and a cap member. These components can be independently assembled and disassembled without welding, allowing quick attachment and detachment while maintaining sealing through the dedicated seal unit with O-ring or gasket elements.
Solution Approach 2:
The seal unit acts as an intermediary element between the radial pin and the inner casing, providing the sealing function that would otherwise require welding. The seal unit includes sealing elements (O-rings, gaskets) that create reliable seals without thermal processes, enabling both good sealing and easy disassembly.
2Strength
If welding is used to fix the radial pin to the inner casing, then the fixing strength is improved, but the device complexity increases
Solution Approach 1:
The fixing device is segmented into modular components (radial pin, seal unit, cap member) that can be independently manufactured and assembled. This modular approach simplifies the overall device complexity compared to welded structures, while maintaining fixing strength through precise mechanical fits and dedicated sealing elements.
Solution Approach 2:
The radial pin includes self-aligning features such as tapered portions and engagement surfaces that automatically position the component correctly during assembly. The cap member threads onto the radial pin to secure it in place, creating a self-fixing mechanism that eliminates the need for complex welding procedures or additional fastening operations.
3Device complexity
If a simple radial pin structure is used, then the device complexity is reduced, but the sealing property deteriorates
Solution Approach 1:
The sealing function is merged with the fixing function by integrating the seal unit with the radial pin and cap member assembly. The seal unit is positioned within the through-hole of the inner casing, and when the cap member is tightened onto the radial pin, it compresses the sealing elements to create a reliable seal, combining both fixing and sealing in a single integrated solution.
Solution Approach 2:
The seal unit serves as an intermediary component that bridges the gap between the simple radial pin structure and the requirement for reliable sealing. It includes sealing elements (O-rings, gaskets) that are compressed between the cap member and the inner casing, providing effective sealing without complicating the overall device structure.
Data Source
AI summary
A fixing device fixes a relative position in a rotational direction of an outer member and an inner member of a stationary body of the rotary machine, and includes: a radial pin that is inserted into a through hole passing through the outer member in a radial direction of a rotary machine and having a stepped portion formed therein to have a larger diameter at a portion on an outer side in the radial direction of the rotary machine than at a portion on an inner side in the radial direction, that has a part on the inner side in the radial direction of the rotary machine to be inserted into a concave portion of the inner member, and that has a flange portion on the outer side in the radial direction of the rotary machine.