Steam Turbine Inner Casing Alignment to Prevent Galling
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Solution Overview
Problem
In steam turbine assembly or disassembly, the inner casing may tilt if its gravity center and the interlocking seat with the outer casing do not coincide, leading to galling and difficulty in disassembly.
Innovation Solution
A tilt adjusting jig is used to maintain and correct the tilt of the inner casing by interposing between the outer and inner casings, employing a bolt, block, and fixing bolt to adjust the inner casing's position without interference.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If the inner casing is assembled or disassembled without a tilt adjusting jig when the fixing position and gravity center are at different positions, then the assembly process is simpler and faster, but the inner casing tilts and causes galling at the interlocking part
Solution Approach 1:
A tilt adjusting jig is introduced as an intermediary device between the inner casing and outer casing. The jig includes a pressing member that contacts the inner casing and a rotating member that adjusts the pressing position, serving as a mediator to correct the tilt caused by the offset between the fixing position and gravity center during assembly or disassembly operations.
2Reliability
If the inner casing is assembled or disassembled without tilt correction, then the assembly process is faster, but galling occurs at the interlocking part making disassembly difficult
Solution Approach 1:
The tilt adjusting jig performs preliminary tilt correction before the final locking of the inner casing to the outer casing. By adjusting the pressing position of the pressing member through rotation of the rotating member, the system preliminarily corrects any tilt that would otherwise lead to galling and assembly failure, ensuring reliable assembly before final fixation.
Data Source
AI summary
An assembly or disassembly method for a casing of a steam turbine in which an inner casing is installed in an outer casing, and the inner casing and the outer casing are fixed at a fixing position, wherein when the inner casing is assembled or disassembled in a state where the fixing position and a gravity center of the inner casing are at different positions in an axial direction of the inner casing, a tilt adjusting jig is interposed between the outer casing and the inner casing so that the assembly or disassembly of the casing is performed while maintaining a tilt of the inner casing with the tilt adjusting jig.