Steam Turbine Casing Deformation Measurement
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Solution Overview
Problem
Existing methods for measuring casing deformation in steam turbines are prone to errors and require complex computations, and their application to existing turbines is cumbersome, making it difficult to rapidly assess deformation during operation or when defects occur.
Innovation Solution
A casing deformation measuring apparatus that includes a target mounted on a bolt holding the lagging material and a distance meter to directly measure deformation by calculating the distance to the target, allowing for easy installation and operation without removing the lagging material, and reducing computational complexity.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If deformation amount is computed from temperature using a thermometer passed through a bolt, then deformation measurement is achieved, but measurement precision deteriorates due to errors between computed and actual values
Solution Approach 1:
The patent replaces the temperature-based computational method with a direct mechanical measurement system. A scale (distance meter) directly measures the distance between a reference position on the casing and a target on the bolt, eliminating the need for temperature-based calculations and linear expansion coefficient assumptions. This direct mechanical measurement provides more reliable and accurate deformation data.
Solution Approach 2:
The patent introduces a target mounted on the bolt as an intermediary element. This target serves as a reference point that moves with the bolt, allowing the scale to indirectly measure bolt elongation (which corresponds to casing deformation) without direct contact with the deformation zone. This intermediary approach enables accurate measurement while maintaining the existing bolt structure.
2Measurement precision
If deformation amount is computed from temperature, then deformation measurement is achieved, but device complexity increases due to complicated analysis requirements
Solution Approach 1:
The patent replaces complex thermal-field computational analysis with a simple mechanical distance measurement system. Instead of requiring temperature measurements, linear expansion coefficients, and computational algorithms, the system uses a scale to directly measure the distance between fixed and moving reference points, dramatically simplifying the measurement process while maintaining accuracy.
Solution Approach 2:
The existing bolt structure serves a dual purpose: it continues to hold the lagging material while simultaneously functioning as a deformation indicator through its elongation. The target mounted on the bolt automatically tracks deformation without requiring separate sensors or complex analysis systems, allowing the structure to inform about its own state.
3Measurement precision
If a thermometer is passed through a bolt to measure deformation, then deformation measurement is achieved, but ease of operation deteriorates due to special structure requirements
Solution Approach 1:
The patent introduces a target as an intermediary element that can be easily attached to the existing bolt structure. This target serves as a measurement reference point that does not interfere with the bolt's primary function of holding the lagging material, allowing the measurement system to be added without modifying the existing structure significantly.
Solution Approach 2:
The existing bolt structure is made multi-functional: it continues to serve its original purpose of securing the lagging material while simultaneously serving as a deformation indicator through its elongation. The measurement system leverages this dual functionality, eliminating the need for separate dedicated measurement hardware and simplifying installation on existing turbines.
4Measurement precision
If a special structure with thermometer through bolt is used, then deformation measurement is achieved, but productivity deteriorates due to manpower requirements for installation
Solution Approach 1:
The existing bolt and lagging material structure serves the measurement function without requiring additional installation work. The target is simply mounted on the existing bolt, and the scale is positioned to measure the distance, allowing rapid deployment without manual installation of complex measurement hardware or disassembly of existing components.
Solution Approach 2:
The patent extracts only the essential measurement function from the complex thermometer-based system. By using a simple scale to measure the distance between fixed and moving reference points on the existing structure, it eliminates the need for installing specialized measurement devices while retaining the ability to measure deformation, thereby increasing productivity.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
Enables direct and accurate measurement of casing deformation, facilitating quick response to defects and reducing computational load, while being easily applicable to existing steam turbines.
Implementation Method 1
a distance meter that is disposed in an opposing relation to the target on the outer side in a diametrical direction of the casing and measures a distance to the target
Data Source
AI summary
Provided is a casing deformation amount measuring apparatus for a steam turbine including a casing, a plurality of nuts fixed to an outer surface of the casing, a plurality of bolts individually screwed, at each one side end portion thereof, in the nuts and projecting to an outer side in a diametrical direction of the casing from the outer surface of the casing, and a lagging material held by the plurality of bolts and covering the casing. The casing deformation amount measuring apparatus includes a target mounted on another side end portion of one of the bolts and exposed to the outer side in a diametrical direction of the casing with respect to the lagging material, and a distance meter that is disposed in an opposing relation to the target on the outer side in a diametrical direction of the casing and measures a distance to the target.