Turbomachine Inner Casing Disassembly via Waisted Shank Bolts
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Solution Overview
Problem
Existing turbomachine disassembly methods require complex procedures and special tools due to the need for radial support and reconnection of guide rings during the removal of inner casing parts, especially when the rotor is installed, making the process cumbersome and inaccessible for the lower half of the outer casing.
Innovation Solution
The use of waisted shank bolts with threads on both ends and washers between nuts and flanges allows for easier disassembly by enabling 180° rotation and removal of the inner casing's lower part without special tools, as the bolts are designed to be untightened from the screw heads, simplifying the process and reducing the need for complex tooling.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If guide ring is installed and radial supporting means are used during rotation, then the inner casing lower part can be removed, but special tools and complex procedures are required
Solution Approach 1:
The patent extracts the supporting function from separate radial supporting means and integrates it directly into the inner casing structure through protrusions and recesses. This eliminates the need for external guide rings and special supporting tools, allowing the inner casing lower part to be rotated and removed using only the casing's own structural features.
Solution Approach 2:
The inner casing is designed to support itself during the disassembly process. The protrusions on the lower part engage with recesses in the upper part, creating self-supporting structures that enable rotation and removal without requiring external radial supporting means or special tools.
2Ease of operation
If connecting bolts are used between guide ring and inner casing lower part, then smooth removal is achieved, but special tools and increased complexity are needed
Solution Approach 1:
The patent merges the connecting function into the flanged connection structure itself. The protrusions and recesses act as integrated connecting elements that replace separate connecting bolts between guide ring and inner casing. This unified structure enables smooth removal while eliminating the need for special connection plates and bolts.
Solution Approach 2:
The flanged connection with protrusions and recesses serves multiple functions: it provides structural support during rotation, enables connecting and disconnecting operations, and facilitates smooth removal. This multi-functional design replaces multiple specialized components with a single universal connection mechanism.
3Reliability
If flanged connection with bolts and nuts is used, then casing stability during operation is maintained, but disassembly requires tool handling and accessibility issues
Solution Approach 1:
The patent inverts the traditional bolt tightening approach by designing protrusions that engage with recesses in a way that naturally guides the disassembly process. Instead of requiring workers to access and untighten bolts from difficult positions, the structural engagement allows rotation and removal to proceed in the opposite direction of conventional disassembly, improving accessibility.
Data Source
Figure 1a~2
Figure 3~4
AI summary
A turbine, especially gas turbine, comprises an outer casing and an inner casing surrounded by said outer casing, whereby said outer casing and inner casing are coaxially arranged with respect to a machine axis, whereby said outer casing and inner casing are each divided in a split plane (15) into an upper part and a lower part (11b, 12b), and whereby said upper and lower parts (11b, 12b) are connected with each other in said split plane (15) by means of a flanged connection. The disassembly process is improved by the flanged connection of the upper and lower part (12b) of said inner casing comprising a plurality of bolts (18), which extend each through through holes (26) in respective flanges (25) of said flanged connection of said inner casing, protrude from said through holes (26) at both ends with a threaded section, and are tightened by means of nuts (19, 22) screwed on said threaded sections at both ends of said bolt (18).